Key Terms from textbook + additional info Flashcards
Learn the full glossary! (642 cards)
1
Q
Aminoacyclase
A
Enzyme used to produce pure samples of L-amino acids
2
Q
Abiotic Factors
A
Non-living conditions in a habitat
3
Q
Abscission
A
The fall of leaves
4
Q
Acetyl Coenzyme A
A
A molecule that enters the Krebs cycle from glycolysis through a linking reaction when coenzyme A combines with an acetyl group
5
Q
Acetylation
A
Addition of an acetyl group
6
Q
Action Potential
A
The change in the potential difference across the neurone membrane of the axon when stimulated (approx + 40mV)
7
Q
Activation Energy
A
The energy required to initiate a reaction
8
Q
Active Site
A
Area of an enzyme with a shape complementary to a specific substrate, allowing the enzyme to bind a substrate with specificity.
9
Q
Active Transport
A
Movement of particles across a plasma membrane against a concentration gradient. Energy (ATP) is required
10
Q
Adenosine Diphosphate (ADP)
A
A nucleotide composed of a nitrogenous base (adenine), a pentose sugar and two phosphate groups. Formed by the hydrolysis of ATP (which contains three phosphate groups), releasing a phosphate ion and energy through the process of dephosphorylation.
11
Q
Adenosine Triphosphate (ATP)
A
A nucleotide composed of a nitrogenous base (adenine), a pentose sugar and three phosphate groups. The universal energy currency for cells.
12
Q
Agglutinins
A
Chemicals (antibodies) that cause pathogens to clump together so they are easier for phagocytes to engulf and digest.
13
Q
Alcoholic Fermentation
A
Fermentation that results in the production of ethanol
14
Q
Alkaloids
A
Bitter-tasting compounds found in plant leaves that may affect the metabolism of animals or insects eating them or poison them. Are also the basis of many drugs. E.g: caffeine
15
Q
Allele
A
Version of a gene
16
Q
Allele Frequency
A
The relative frequency of a particular allele in a population at a given time
17
Q
Alleles
A
Different versions of the same gene
18
Q
Allopatric speciation
A
Speciation that occurs as a result of a physical barrier between populations
19
Q
Amino Acids
A
Monomer used to build polypeptides and thus proteins
20
Q
Ammonification
A
Conversion of nitrogen compounds in dead organic matter or waste into ammonium compounds by decomposers.
21
Q
Anabolic Steroids
A
Steroid drugs used illegally by some athletes and body builders to increase muscle mass.
22
Q
Anabolism (Anabolic)
A
Reactions of metabolism that construct molecules from smaller units. These reactions require energy from thy hydrolysis of ATP.
23
Q
Anaerobic respiration
A
Respiration in the absence of oxygen
24
Q
Analogous structures
A
Structures that have adapted to perform the same function but have a different origin.
(Used in comparative anatomy and within convergent evolution)
25
Anaphase
Third stage of mitosis when chromatids are separated to opposite poles of the cell.
26
Antibiotic-resistant bacteria
Bacteria that undergo mutation to become resistant to an antibiotic and then survive to increase in number.
27
Antibiotics
A chemical or compound that kills or inhibits the growth of bacteria.
28
Antibodies
Y-shaped glycoproteins made by B cells (plasma) of the immune system in response to the presence of an antigen.
29
Antidiuretic hormone (ADH)
Hormone that increases the permeability of the distal convoluted tubule and the collecting duct to water.
30
Antigen
Identifying chemical on the surface of a cell that triggers an immune response
31
Antigen-antibody complex
The complex formed when an antibody binds to an antigen
32
Antigen-presenting cell (APC)
A cell that processes and displays foreign antigens complexed with major histocompatibility complexes on their surfaces for recognition by certain lymphocytes (T cells). E.g: dendritic cells, macrophages, langerhans cells and B cells
33
Antisense strand
The strand of DNA that runs 3' to 5' and is complementary to the sense strand. It acts as a template strand during transcription
34
Anti-toxins
Chemicals (antibodies) that bind to toxins produced by pathogens so they no longer have an effect
35
Apical Dominance
The growth and dominance of the main shoot as a result of the suppression of lateral shoots by auxin.
36
Apoplast
The cell walls and intercellular spaces of plant cells.
37
Apoplast Route
Movement of substances (water and dissolved mineral ions) through the cell walls and cell spaces by diffusion and into the cytoplasm by active transport.
38
Apoptosis
Programmed and controlled cell death. Important in controlling the body form and in the removal of damaged or diseased cells.
39
Arrhythmia
An abnormal rhythm of the heart
40
Artefacts
Objects or structures, seen through a microscope, that have been created during the processing and preparation of a specimen on a microscopic slide.
41
Artificial Active Immunity
Immunity which results from exposure to a safe form of a pathogen, E.g: by vaccination
42
Artificial Passive Immunity
Immunity which results from the administration of antibodies from another animal against a dangerous pathogen
43
Artificial selection (selective breeding)
Only a few individuals within a population are selected for their advantageous characteristics and bred. E.g: the breeding of pedigree animals or of human food crops.
44
Artificial twinning (Embryo splitting)
The process of producing monozygotic twins artificially.
45
Aseptic techniques
Techniques used to culture microorganisms in sterile conditions so they are not contaminated with unwanted microorganisms.
46
Asexual reproduction (mitosis)
The production of genetically identical offspring from a single parent.
47
Assimilates
the products of photosynthesis that are transported around a plant E.g: sucrose
48
Atrial Fibrillation
An abnormal rhythm of the heart when the atria beat very fast and incompletely.
49
Atrio-ventricular node (AVN)
Stimulates the ventricles to contract (through electrical conduction) after imposing a slight delay to ensure atrial contraction is complete.
50
Autoimmune disease
A condition or illness resulting from an autoimmune response. E.g: Rheumatoid Arthritis, Lupus, Type 1 diabetes
51
Autoimmune response
Response when the immune system acts against its own cells and destroys healthy tissue in the body
52
Autonomic nervous system
Part of the nervous system that is under subconscious control. (input from internal sensory receptors + output to smooth muscle and glands)
53
Autosomal Linkage
Genes present on the same, non-sex chromosome
54
Autotrophic
Organisms that synthesize complex organic molecules from inorganic molecules via photosynthesis E.g: plants
55
Auxins
Plant hormones that control cell elongation, prevent leaf fall, maintain apical dominance, produce tropic responses, and stimulate the use of ethene in fruit ripening.
56
B effector cells
B lymphocytes that divide to form plasma cell clones
57
B lymphocytes (B cells)
lymphocytes which mature in the bone marrow and that are involved in the production of antibodies
58
B memory cells
B lymphocytes that live a long time and provide immunological memory of the antibody needed against a specific antigen
59
Baroreceptors
receptors which detect changes in pressure
60
Batch fermentation
an industrial fermentation that runs for a set time (antibiotics E.g: penicillin and Enzymes)
61
Belt transect
Two parallel lines are marked along the ground and samples are taken of the area at specified points
62
Benedict's reagent
An alkaline solution of copper(II) sulfate used in the chemical tests for reducing (all monosaccharides) and non-reducing sugars (most commonly sucrose). A brick-red precipitate indicates a positive result.
63
Beta pleated sheet
sheet-like secondary structure of proteins, contains hydrogen bonds.
64
Binomial nomenclature
the scientific naming of a species with a Latin name made of two parts- first genus (capital letter), second is species (all lower case). In italics - when writing underline.
65
Biodiversity
the variety of living organism present in an area.
66
Bioinformatics
the development of the software and computing tools needed to analyse and organise raw biological data E.g: algorithms, mathematical models and statistical tests that help make sense of enormous quantities of data.
(new area of bioscience that was developed due to the development of DNA profiling and DNA sequencing)
67
Biomass
mass of living material
68
Bioremediation
the use of microorganisms to break down pollutants and contaminants in the soil or water.
E.g: naturally using bacteria in the sea after an oil spill. Artificially using GM bacteria to remove mercury contamination in water
69
Biotic factors
Living components of an ecosystem
70
Biuret test
Chemical test for proteins; peptide bonds form violet coloured complexes with copper ions in alkaline solutions.
71
Bohr effect
The effect of carbon dioxide concentration on the uptake and release of oxygen by haemoglobin.
As the partial pressure of carbon dioxide rises, haemoglobin gives up oxygen more easily.
72
Bohr shift
As the proportion of carbon dioxide increases, the oxygen dissociation curve for haemoglobin moves to the right.
73
Bowman's capsule
Cup-shaped structure that contains the glomerulus and is the site of ultrafiltration in the kidney.
74
Bradycardia
A slow heart rhythm of 60 beats per minute
75
Breathing rate
the number of breaths (inhalation and exhalation) taken per minute
76
Bulk transport
A form of active transport where large molecules or whole bacterial cells are moved into or out of a cell by endocytosis or exocytosis.
77
Bundle of His
Conducting tissue composed of purkyne fibres that passes through the septum of the heart.
78
Callose
A polysaccharide contained Beta 1-3 linkages and Beta 1-6 linkages between the glucose monomers that is important in the plant response to an infection.
Callose is deposited between plant cell walls + plasma membranes + at the plasmodesmata during times of stress E.g: pathogen invasion limiting their spread
79
Calvin Cycle
The cyclical light independent reactions of photosynthesis.
- Occurs in the stroma of the chloroplasts
- Here, the ATP and reduced NADP from the light dependent stage supply the energy and hydrogen to make glucose from CO2.
- 3 stage Cycle: Carbon fixation (CO2 + RuBP using Rubisco = 2GP), Reduction (light dependent products used to reduce + phosphorylate 2GP = 2TP), Regeneration (left TP into RuBP)
80
Carbaminohaemoglobin
The compound formed when carbon dioxide combines with haemoglobin
81
Carbohydrates
Organic polymers composed of the elements carbon, hydrogen and oxygen, usually in the ratio Cx (H20)y. Also known as saccharides or sugars.
82
Carbonic anhydrase
Enzyme which catalyses the reversible reaction between carbon dioxide + water = carbonic acid
83
Cardiac cycle
The events of a single heartbeat composed of diastole and systole.
- Diastole (both atria + ventriles relax, pressure in arteries > ventricles = closing of semi-lunar valves [middle], blood flows into the atria)
- Atrial Systole (both atria contract same time, pressure in atria > ventricles, blood flows through open AV valves into ventricles)
- Ventricular systole (both ventricles contract same time, pressure ventricles > atria + arteries = AV valves close + semi-lunar valves open, blood leaves heart)
84
Carrier
A person who has one copy of a recessive allele coding for a genetically inherited condition.
E.g: sex linked condition; female hemophiliac carriers
85
Carrier Proteins
Membrane proteins that play a part in the transport of substances through a membrane.
86
Carrying Capacity
The maximum population size that an environment can carry
87
Cartilage
Strong, flexible connective tissue found in many areas of the bodies of humans and other animals.
E.g: incomplete rings in trachea to prevent collapsing, bronchi (smaller)
88
Catabolism (Catbolic)
Reactions of metabolism that break molecules down into smaller units. These reactions release energy.
89
Catalase
An enzyme that catalyses the breakdown of hydrogen peroxide
90
Cell cycle
The highly ordered sequence of events that takes place in a cell, resulting in division of the nucleus and the formation of two genetically identical daughter cells.
- Interphase (G1, G2, S)
- Mitosis
- Cytokinesis
91
Cell Signalling
A complex system of intercellular communication.
92
Cellulose
A polysaccharide formed from beta glucose molecules where alternate beta glucose molecules are turned upside down. It is unable to coil or form branches but makes hydrogen bonds with other cellulose molecules to produce strong and insoluble fibres. Major component of plant cell walls.
93
Cell wall
A strong but flexible layer that surrounds some cell-types. E.g: plant cells
94
Central Nervous System (CNS)
Consists of the brain and spinal cord
| - relay neurones
95
Centrioles
Small, hollow cylinders that are a component of the cytoskeleton of most eukaryotic cells (all animal cells, some plant cells), composed of microtubules (tiny protein cylinders)
- forms spindle fibres to move chromosomes during mitosis + meiosis
96
Cerebrum
Controls voluntary actions, such as learning, memory, personality and conscious thought.
97
Cerebellum
Co-ordinates and controls unconscious functions such as posture, balance and non-voluntary movement.
98
Centromere
Region at which two chromatids are held together
99
Channel Proteins
Membrane proteins that provide a hydrophilic channel through a membrane
100
Checkpoints
Control mechanisms of the cell cycle
- G1 checkpoint: cell checks that the chemicals needed for replication are present and for any damage to the DNA before entering S phase
- G2 checkpoint: cell checks whether all the DNA has been replicated without any damage before the cell can enter mitosis
- Metaphase checkpoint: cell checks that all the chromosomes are attached to the spindle before mitosis can continue
101
Chemiosmosis
The synthesis of ATP driven by a flow of protons across a membrane
102
Chemoreceptors
Receptors which detect chemical changes
103
Chi-squared formula
Formula used to determine the significance of the difference between observed and expected count data.
104
Chiasmata
Sections of DNA, which became entangled during crossing over, break and rejoin during anaphase 1 of meiosis sometimes resulting in an exchange of DNA between bivalent chromosomes, forming recombinant chromatids and providing genetic variation.
105
Chloride shift
The movement of bicarbonate ions into the red blood cells as hydrogen ions move out to maintain the electrochemical equilibrium.
106
Chlorophyll
Green pigment that captures light in photosynthesis. Chlorophyll a (primary pigment) and chlorophyll b (accessory pigment).
107
Chloroplasts
Organelles that are responsible for photosynthesis in plant cells. Contain chlorophyll pigments, which are the site of the light reactions of photosynthesis.
108
Chromatids
Two identical copies of DNA (a chromosome) held together at the centromere
109
Chromatin
Uncondensed DNA in a complex with histones
110
Chromosomes
Structures of condensed and coiled DNA in the form of chromatin. Chromosomes become visible under the light microscope when cells are preparing to divide (prophase).
111
Crossing Over
During Prophase 1 of meiosis 1, homologous pairs of chromosomes come together and pair up. The chromatids twist around each other and bits of chromatids swap over. The chromatids still contain the same genes but now have a different combination of alleles.
112
Circulatory system
The transport system of an animal
113
Citrate
Six carbon molecule formed in Krebs cycle by the combination of oxaloacetate and acetyl coenzyme A.
114
Climax Community
Final stage in succession, where the community is said to be in a stable state.
115
Clonal Expansion
The mass proliferation of antibody-producing cells by clonal selection.
116
Clonal Selection
The theory that exposure to a specific antigen selectively stimulates the proliferation of the cell with the appropriate antibody to form numerous clones of these specific antibody-forming cells (clonal expansion)
117
Clones
The genetically identical offspring produced as a result of cloning.
118
Cloning
A way of producing offspring by asexual reproduction
119
Closed circulatory system
A circulatory system where the blood is enclosed in blood vessels and does not come into direct contact with the cells of the body beyond the blood vessels.
E.g: Fish and mammals
120
Clostridium difficile (C. difficile)
A species of Gram positive bacteria that is resistant to most antibiotics
121
Codominance
When different alleles of a gene are equally dominant and both are expressed in the phenotype. Ratio 2:1:1
122
Codon
A three-base sequence of DNA or RNA that codes for an amino acid
123
Coenzyme A
Coenzyme with important roles in the oxidation of pyruvate in Krebs cycle and in the synthesis and oxidation of fatty acids.
124
Cofactors
Non-protein components necessary for the effective functioning of an enzyme.
E.g: iron, calcium, chloride, zinc ions
125
Cohesion-tension theory
The best current model explaining the movement of water through a plant during transpiration
126
Collecting duct
Final part of the tubule that passes through the renal medulla and the place where the hypertonic urine is produced if needed. The permeability of the walls is affected by ADH levels and it is the main site of water balancing.
127
Communicable diseases
Diseases that can be passed from one organism to another, of the same or different species.
128
Community
All the populations of living organisms in a particular habitat.
129
Companion cells
The active cells found next to sieve tube elements that supply the phloem vessels with all of their metabolic needs. Used in translocation.
130
Competitive inhibitor
An inhibitor that competes with a substrate to bind to active site on an enzyme due to its similar shape with the substrate.
131
Complementary base pairing
Specific hydrogen bonding between nucleic acid bases. Adenine(A) binds to thymine(T) or uracil(U) with two bonds and cytosine(C) binds to guanine(G) with three bonds.
132
Compound light microscope
A light microscope which uses two lenses to magnify an object; the objective lens - placed near to the specimen, and an eyepiece lens - through which the specimen is viewed
133
Condensation Reaction
A reaction between two molecules resulting in the formation of a larger molecule and the release of a water molecule. The opposite reaction to a hydrolysis reaction.
134
Computational Biology
The study of biology using computational techniques to analyse large amounts of data.
- builds theoretical models or biological systems
- which can be used to predict what will happen in different circumstances
- developed bioscience due to the development of DNA profiling + DNA sequencing
135
Conservation
The maintenance of biodiversity through human action or management
136
Consumer
Organism that obtains its energy by feeding on another organism.
137
Continuous fermentation
An industrial fermentation where culture broth is removed continuously and more nutrient medium added
138
Continuous variation
A characteristic that can take any value within a range e.g. height.
139
Contrast
staining or treating specific cell components so they are visible compared to untreated components
140
Convergent evolution
Organisms evolve similarities because the organisms adapt to similar environments or other selection pressures
141
Correlation coefficient
Statistical text used to consider the relationship between two sets of data.
142
Cortex
The dark outer layer of the kidney containing the Bowman's capsules and glomeruli
143
Countercurrent exchange system
A system for exchanging materials or heat when the two different components flow in opposite directions past each other.
E.g: in the circulatory system of fish
144
Counterstain
Application of second stain with a contrasting colour to sample for microscopy.
145
Cristae
Fold of inner mitochondrial membranes, increases the surface area where reactions of the electron transfer chain can take place. Site of oxidative phosphorylation
146
Culture
Growing living matter in vitro E.g: microorganisms in specifically prepare nutrient medium.
147
cyclic AMP
Cyclic adenosine monophosphate, a molecule that acts as an important second messenger in many biological systems
E.g: lac operon
148
cycic photophosphorylation
Synthesis of ATP involving only photosystem 1
149
Cytokines
Cell-signalling molecules produced by mast cells in damaged tissues that attract phagocytes to the site of infection or inflammation
150
Cytokinesis
Cell division stage in the mitotic phase of the cell cycle that results in the production of two identical daughter cells.
151
Cytolysis
The bursting of an animal cell caused by increasing hydrostatic pressure as water enters by osmosis.
152
Cytoplasm
Internal fluids of cells, composed of cytosol (water, salts and organic molecules), organelles and cytoskeleton. Where majority of cell reactions take place.
153
Cytoskeleton
A network of fibres in the cytoplasm of a eukaryotic cell.
Major type of filaments that make up cytoskeleton:
- actin filaments
- microtubules
- intermediate filaments
154
Deamination
The removal of the amino group from amino acids.
E.g: it is the most important role of the liver in protein metabolism. Converts amino acids into ammonia through deamination
155
Decarboxylation
The removal of carbon dioxide
156
Deciduous Plants
plants that lose their leaves for part of the year
157
Decomposer
Organism that breaks down dead organisms releasing nutrients back into the ecosystem
E.g: bacteria, fungus
158
Decomposition
Chemical reaction in which a compound is broken down into simpler compounds or into its constituent elements.
159
Dehydrogenation
The removal of a hydrogen atom
160
Deletion
A mutation where one or more nucleotides are deleted and lost from the DNA strand
161
Denitrification
conversion of nitrates to nitrogen gas
162
Denatured
Change in tertiary structure of a protein or enzyme, resulting in loss of normal function
163
Deoxyribonucleic acid (DNA)
The molecule responsible for the storage of genetic information
164
Depolarisation
A change in potential difference from negative to positive across the membrane of a neurone.
165
Detoxification
Removal or breakdown of toxins
166
Detritivore
Organism which speeds up decay by breaking down detritus into smaller pieces.
E.g: earthworm
167
Diabetes mellitus
medical condition which affects a person's ability to control their blood glucose concentration
168
Diastole
The stage in which the heart relaxes and the atria and then the ventricles fill with blood
169
Dicotyledonous plants (dicots)
Plants that produce seeds containing two cotyledons, which act as food stores for the developing embryo and form the first leaves when the seed germinates.
170
Differential staining
Using specific stains to distinguish between different types of cells.
171
Differentiation
The process of a cell becoming differentiated. Involves the selective expression of genes in a cell's genome.
172
Digenic inheritance
A characteristic controlled by two genes
173
Dihybrid inheritance
A characteristic inherited on two genes. Ratio 9:3:1:1
174
Diploid
Normal chromosome number; two chromosomes of each type - one inherited from both parents
175
Directional selection
Natural selection that favours one extreme phenotype
| E.g: peppered moths during industrial revolution
176
Disaccharide
A molecule comprising two monosaccharides, joined together by a glycosidic bond
E.g: Lactose (glucose + galactose), Sucrose (glucose + fructose), Maltose (glucose + glucose)
177
Discontinuous variation
A characteristic that can only result in discrete values
| E.g: blood type
178
Disruptive selection
Natural selection that favours both extremes of a given phenotype
179
Distal convoluted tubule
The second twisted section of the nephron where the permeability of the walls varies in response to ADH levels in the blood
180
Divergent evolution
Species diverge over time into two different species, resulting in a new species becoming less like the original one
181
DNA helicase
Enzyme that catalyses the unwinding and separating of strands in DNA replication.
182
DNA polymerase
Enzyme that catalyses the formation of phosphodiester bonds between adjacent nucleotides in DNA replication.
183
DNA profiling (DNA finger printing)
Producing an image of the patterns in the non-coding DNA of an individual.
Used in:
- forensics
- paternal testing
- likelihood of inheriting a genetic disease
184
DNA replication
The semi-conservative process of the production of identical copies of DNA molecules
185
DNA sequencing
Working out the sequence of bases in a strand of DNA
186
Dominant allele
Version of the gene that will always be expressed if present
187
Dominant species
The most abundant species in an ecosystem
188
Double circulatory system
A circulatory system where the blood travels twice through the heart for each complete circulation of the body. In the fist circulation blood is pumped by the heart to the lungs. In the second circulation oxygenated blood is pumped by the heart to the brain and body to supply cells with oxygen
E.g: In humans
189
Ecological efficiency
Efficiency with which energy or biomass is transferred from one trophic level to the next
190
Ecosystem
All the interacting living organisms and the non living conditions of a given area, it is dynamic.
191
Ecotourism
Tourism directed towards natural environments, intended to support conservation efforts.
192
Ectopic heartbeat
Extra heartbeats that are out of the normal rhythm
193
Ectotherms
Animals that use their surroundings to warm their bodies so their core temperature is heavily dependent on the environment.
E.g: reptiles
194
Effector
Muscle or gland which carries out body's response to a stimulus.
195
Elastic recoil
The ability to return to original shape and size following stretching. Particularly of the alveoli of the lungs and of the arteries.
196
Electrocardiogram (ECG)
A technique for measuring tiny changes in the electrical conductivity of the skin that results from the electrical activity of the heart. This produces a trace which can be used to analyse the health of the heart.
197
Electron carriers
Proteins that accept and release electrons
198
Electron microscopy
Microscopy using a microscope that employs a beam of electrons to illuminate the specimen. As electrons have a much smaller wavelength than light they produce images with higher resolutions than light microscopes
199
Electrophoresis
A type of chromatography that relies on the way charged particles move through a gel under the influence of an electrical current. It is used to separate nucleic acid fragments or proteins.
200
Electroporation
The use of a very tiny electric current to transfer genetically engineered plasmids into bacteria or to get DNA fragments directly into eukaryotic cells (e.g in somatic cell nuclear transfer)
201
Emulsion test
Laboratory test for lipids using ethanol - a white emulsion indicates the presence of a lipid.
202
End-product inhibition
The product of a reaction inhibits the enzyme required for the reaction.
203
Endocrine glands
Group of specialized cells which secrete hormones
204
Endocytosis
The bulk transport of materials into cells via invagination of the cell-surface membrane forming a vesicle
205
Endosymbiosis
The widely-accepted theoretical process by which eukaryotic cells evolved from prokaryotic cells.
206
Endothermic
Reactions that absorb energy
207
Endotherms
Animals that rely on their metabolic processes to warm their bodies and maintain their core temperature
208
Enucleated
With the nucleus removed
209
Enzyme-product complex
Complex formed as a result of an enzyme-catalysed reaction, when a substrate is converted to a product or products while bound to the active site of an enzyme
210
Enzymes
Biological catalysts that interact with substrate molecules to facilitate chemical reactions. Usually globular proteins
211
Enzyme-substrate complex
Complex formed when a substrate is bound to the active site of an enzyme
212
Epidemic
When a communicable disease spreads rapidly to a lot of people at a local or national level
213
Epigenetics
External control of genetic regulation
214
Epistasis
The effect of one gene on the expression of another gene. The interaction of genes at different loci.
E.g: gene regulation
215
Euchromatin
loosely packed DNA
216
Eukaryotes
multicellular eukaryotic organisms like animals, plants and fungi and single-celled protoctista.
217
Eukaryotic cells
Cells with a true nucleus and other membrane-bound organelles.
218
ex situ conservation
Conservation methods out of their natural habitats
| E.g: zoos, aquariums, seed banks
219
Exchange surfaces
Surfaces over which materials are exchanged from onw area to another
220
Excretion
The removal of the waste products of metabolism from the body.
221
Exocytosis
The bulk transport of materials out of cells. Vesicles containing the material fuse with the cell-surface membrane and the contents are released to the outside of the cell
E.g: the neurotransmitter acetylcholine in a cholinergic synapse
222
Exoskeleton
An external skeleton of some organisms
| E.g: insects
223
Exothermic
Reactions that release energy
224
Expiratory reserve volume
The extra amount of air that can be forced out of the lungs over and above the normal exhalation (tidal volume)
225
Facilitated Diffusion
Diffusion across a membrane through protein channels
226
Facultative anaerobes
Organisms that can respire anaerobically or aerobically
| E.g: yeast
227
FAD
A coenzyme that acts as a hydrogen acceptor in Krebs cycle
228
Fatty acids
Long chain carboxylic acids used in the formation of triglycerides and phospholipids
- Unsaturated (at least one double bond)
- Saturated (no double bonds)
229
Fermentation
Anaerobic respiration without the involvement of an electron transport chain
230
Fibrous Proteins
Long, insoluble, structural proteins
E.g:
- Collagen = mechanical strength, withstand high pressures; bones, tendon cartilage, connective tissue
- Keratin = many disulfide bridges, hard and strong; fingernails, hair, horns, hooves, feathers
- Elastin = elastic, stretch + recoil; skin, lungs, blood vessels, bladder
231
Fluid-mosaic model
Model of the structure of a cell membrane in which phospholipids within the phospholipid bilayer are free to move and proteins of various shapes and sizes are embedded in various positions.
232
Forensics
The application of science to the law, commonly in solving crimes
233
Fossils
The remains or impression of science to the law, commonly in solving crimes
234
Founder Effect
When a few individuals of a species colonise a new area, their offspring initially experience a loss in genetic variation, and rare alleles can become much more common in the population.
235
Fungi
Biological kingdom containing yeasts, moulds and mushrooms
236
Gametes
Haploid sex cells produced by meiosis in organisms that reproduce sexually
237
Gaseous exchange system
The complex systems in which the respiratory gases oxygen and carbon dioxide are exchanged in an organism
238
Gene
A section of DNA that contains the complete sequence of bases (codons) to code for a protein
239
Gene banks
Store of genetic material
- keep samples of wild + domesticated seed varieties
-store biological samples such as sperm + eggs, frozen
= used to increase genetic diversity by outbreeding
240
Gene flow
When alleles are transferred from one population to another by interbreeding
241
Gene pool
Sum total of all the genes in a population at a given time
242
Genetic bottleneck
When large numbers of a population die prior to reproducing, leading to reduced genetic biodiversity within the population.
243
Genetic code
The sequences of bases in DNA are the 'instructions' for the sequences of amino acids in the production of proteins
244
Genetic drift
Random change of allele frequency
245
Genetic variation
A variety of different combinations of alleles in a population
246
Genome
All of the genetic material of an organism
247
Genotype
Genetic makeup of an organism
248
Geotropism
The growth response of plants towards gravity
249
Germ line gene therapy
Inserting a healthy allele into the germ cells (gametes) or into a very early embryo (zygote)
250
Gibberellins
Plant hormones that cause stem elongation, trigger the mobilisation of food stores in a seed at germination and stimulate pollen tube growth in fertilisation
251
Gills
The gaseous exchange organs of fish, comprised of gill plates, gill filaments and gill lamellae.
252
Globular proteins
Spherical, water-soluble proteins
253
Glomerular filtration rate (GFR)
A test used to estimate the volume of blood filtered by the glomeruli each minute, used to indicate a loss of function in the kidneys.
254
Glucoamylase
Enzyme used to convert dextrins to glucose
255
Gluconeogenesis
Production of glucose from non-carbohydrate sources
256
Glucose
A monosaccharide with the chemical formula C6H12O6. One of the main products of photosynthesis in plants
257
Glucose isomerase
Enzyme used to produce fructose from glucose
258
Glycerate-3-phosphate
Compound formed in Calvin Cycle after carbon fixation
259
Glycerol
Alcohol found in trigylcerides (1 glycerol ester bond 3 fatty acids producing 3 water mols)
260
Glycogen
A branched polysaccharide formed from alpha glucose molecules. A chemical energy store in animal cells.
261
Glycogenesis
Production of glycogen from glucose
262
Glycogenolysis
Process in which glycogen stored in the liver and muscle cells is broken down into glucose
263
Glycolipids
Cell-surface membrane lipids with attached carbohydrate molecules of varying lengths and shapes
264
Glycoproteins
Extrinsic membrane proteins with attached carbohydrate molecules of varying lengths and shapes
265
Glycosidic bond
A covalent bond between two monosaccharides
266
Goblet cells
Differentiated cells specialised to secrete mucus
267
Golgi Apparatus
Organelle in most eukaryotic cells formed from an interconnected network of flattened, membrane-enclosed sacs, or cisternae. Plays a role in modifying and packaging proteins into vesicles.
268
Gram negative bacteria
Bacteria with cell walls that stain red with Gram stain
269
Gram positive bacteria
Bacteria with cell walls that stain purple-blue with Gram stain
270
Granum (plural grana)
A structure inside chloroplasts composed of a stack of several thylakoids. Contains chlorophyll pigments, where light reactions occur during photosynthesis.
271
Guard cells
Cells that can open and close the stomatal pores, controlling gaseous exchange and water loss in plants.
272
Habitat Biodiversity
The number of different habitats found within an area
273
Haemoglobin
The red, oxygen-carrying pigment of red blood cells
274
Haemoglobinic acid
The compound formed when haemoglobin accepts free hydrogen ions in its role as a buffer in the blood.
275
Haemolymph
The transport medium or 'blood' in insects
276
Haploid
Half the normal chromosome number; one chromosome of each type
277
Hardy-Weinberg equation
Formula used to calculate the frequency of alleles in a population (pop has to be stable and not evolving)
278
Hepatocytes
liver cells
279
Herbivory
The process of animals eating plants
280
Heterochromatin
Tightly packed DNA
281
Heterotrophic
Organisms that acquire nutrients by the ingestion of other organisms
282
Heterozygous
Two different alleles for a characteristic
283
Hexose bisphosphate
The compound that results from the phosphorylation of glucose in glycolysis.
284
Hexose monosaccharide
A monosaccharide composed of six carbons
285
High throughput sequencing (Next Generation sequencing)
New methods of sequencing DNA that are automated, very rapid and much cheaper than the original techniques.
286
Histamines
Chemicals produced by mast cells in damaged tissues that make the blood vessels dilate (causing redness and heat) and the blood vessels leaky (causing swellin and pain)
287
Histones
Proteins that form a complex with DNA called chromatin
288
Homeobox genes (Hox genes)
Regulatory genes responsible for the development of body plans through apoptosis and mitosis
289
Homeodomain
A conserved motif of 60 amino acids found in all homeobox proteins. It is the part of the protein that binds to DNA allowing the protein to act as a transcriptional regulator.
290
Homeostasis
The maintenance of a stable equilibrium in the conditions inside the body.
291
Homologous chromosomes
Matching pair of chromosomes, one inherited from each parent.
292
Homologous structure
A structure which appears superficially different but has the same underlying structure. E.g pentadactyl limb
293
Homozygous
Two identical alleles for a characteristic
294
Hormone
Chemical messengers which travel around the body in the blood stream
295
Humus
Organic component of soil formed by the decomposition of leaves and other plant material by soil microorganisms
296
Hydrolysis reaction
The breakdown of a molecule into smaller molecules requiring the addition of a water molecule. Opposite to condensation reaction
297
Hydrophilic
The physical property of a molecule that is attracted to water
298
Hydrophobic
The physical property of a molecule that is repelled by water
299
Hydrophytes
Plants with adaptations that enable them to survive in very wet habitats or submerged at the surface of water E.g: water lillies, water cress, duck weeds, yellow iris;
- thin, waxy cuticle
- many always open stomata on upper surface
- reduced structure to plant
- wide, flat leaves
- small roots
- large SA of roots and stems under water
- air sacs
300
Hydrostatic pressure
The pressure created by water in an enclosed system
301
Hypothalamus
Regulatory centre for temperature and water balance. The region of the brain above the pituitary gland that contains osmoreceptors involved in osmoregulation and thermoreceptors involved in thermoregulation.
302
Immobilised Enzymes
Enzymes that are attached to an inert support system over which the substrate passes and is converted to product
- adsorption
- ionic/covalent bonding
- entrapment
- encapsulation
303
Immune Response
A biological response that protects the body by recognising and responding to antigens and by destroying substances carrying non-self antigens
304
Immunoglobulins
y-shaped glycoproteins that form antibodies
305
in situ conservation
conservation methods within the natural environment
E.g;
-national parks/wildlife reserves, marine conservation (protected areas)
306
inbreeding
breeding between closely related organisms
307
inbreeding depression
reduced biological fitness due to inbreeding
308
independent assortment
The arrangement of each homologous chromosome pair (bivalent) in metaphase 1 and metaphase 2 of meiosis is independent of each other and results in genetic variation
309
Inflammation
Biological response of vascular tissues to pathogens, damaged cells, or irritants, resulting in pain, heat, redness and swelling
310
Inhibitor
A factor that prevents or reduces the rate of an enzyme catalysed reaction
311
Inner mitochondrial membrane
The inner most of the two mitochondrial membranes. Separates the mitochondrial matrix from the intermembrane space. Is the site where the electron transport chain takes place
312
Insertion
A point mutation where one or more extra nucleotides are inserted into a DNA strand
313
Inspiratory Reserve Volume
The maximum volume of air that can be breathed in over and above a normal inhalation (tidal volume)
314
Insulin
A globular protein involved in the regulation of blood glucose concentration.
Produced by beta cells in islets of langerhans (pancreas) when blood glucose level is too high:
- Insulin binds to membrane-bound receptors on liver and muscle cells (first messenger)
- Activates a secondary messenger resulting in:
- more glucose channels on membrane = more glucose enters cells
- glycogenesis for storage
- more glucose converted to fatss
- increased rate of respiration
- stops cells using sources other than glucose as an energy source
Whereas, glucagon is detected and acts on liver cells
315
Intercostal muscles
The muscles between the ribs that pull the ribs upwards during inhalation (internal intercostal muscles) and downwards during forced exhalation (external intercostal muscles)
316
Interleukins
A type of cytokine produced by T helper cells
317
Interphase
Growth period of the cell cycle, between cell divisions (mitotic phase). Consists of stages G1, G2, S:
- G1 = Cell grows, new organelles + proteins are made
- S= Cell replicates its DNA, ready to divide by mitosis
- G2= Cell keeps growing + proteins needed for cell division are made
318
Interspecific competion
Competition between organisms of different species for the same resource
319
Interspecific variation
The differences between organisms of different species
320
Intraspecific variation
The differences between organisms of the same species
321
Intraspecific competion
Competition between organisms of the same species for the same resource
322
Introns
Regions of non-coding DNA or RNA
323
Iodine test
A chemical test for the presence of starch using a potassium iodide solution. A colour change to purple/black indicates a positive result
324
Ion
An atom or molecule with an overall electric charge because the total number of electrons is not equal to the total number of protons. Anion or Cation
325
Ionic bond
A chemical bond that involves the donating of an electron from one atom to another, forming positive and negative ions held together by the attraction of the opposite charges.
326
Islets of langerhans
Clusters of specialised cells within the pancreas responsible for producing insulin (beta cells) and glucagon (alpha cells LARGER)
Endocrine glands - secreted directly into blood capillaries
327
Acinar cells
Exocrine cells of pancreas that secretes digestive enzymes into pancreatic ducts into the small intestine:
- Amylase
- Lipase
- Trypinogen (inactive protease)
- Sodium Hydrogen Carbonate (as acidity of stomach denatures enzymes)
328
Keystone Species
Species which are essential for maintaining biodiversity - they have a disproportionately large effect on their environment relative to their abundance
329
Kingdom
The second biggest and broadest taxonomic group
- Animalia
- Plantae
- Fungi
- Protoctista
- Bacteria/Prokaryote
330
Lac operon
Operon responsible for the metabolism of lactose
331
Lactase
Enzyme used to hydrolyse lactose to glucose and galactose and produce lactose-free milk
332
Lactose
A disaacharide made up of galactose and glucose monosaccharide
333
Lactate dehydrogenase
Enzyme used in the conversion of pyruvate to lactate
334
Lactate fermentation
Fermentation (in anaerobic respiration) that results in the production of lactate in animal cells
335
Integranal lamellae
Membranous channels which join grana together in a chloroplast
336
Laser scanning confocal microscope
A microscope that employs a laser beam and a a pin-hole aperture to produce an image with a very high resolution
337
Light harvesting system
A group of protein and chlorophyll molecules found in the thylakoid membranes of the chloroplasts in a plant cell.
338
Light microscope
An instrument that uses visible light and glass lenses to enable the user to see objects magnified many times
339
Limiting factor
A factor which limits the rate of a process
340
Line breeding
A form of inbreeding using less closely related organisms
341
Line transect
A line is marked along the ground and samples are taken at specified points
342
Linked genes
Genes present on the same chromosome
343
Lipids
Non-polar macro-molecules containing the elements carbon, hydrogen and oxygen. Commonly known as fats (solid at room temp) and oils (liquid at room temp)
344
Loop of Henle
A long loop of nephron that creates a steep concentration gradient across the medulla
345
Lung surfacant
Chemical mixture containing phospholipids and both hydrophilic and hydrophobic proteins, which coats the surfaces of the alveoli and prevents them collapsing after every breath
346
Lymph
Modified tissue fluid that is collected in the lymph system
Contains:
- White blood cells = Most white blood cells, only enter tissue fluid when there's an infection
- Antibodies(only proteins) = Most plasma proteins are too big to get through capillary walls
- Water = Both tissue fluid and lymph have a higher water potential than blood
- Dissolved solutes (e.g salt) = move freely between blood, tissue fluid and lymph
347
Lymphocytes
White blood cells that make up the specific immune response
348
Lysosomes
Specialised vesicles containing hydrolytic enzymes for the breakdown of waste materials within a cell e.g. phagocytosis
349
Macromolecules
Large complex molecules with a large molecular weight
350
Maltose
Disaacharaide composed of two glucose molecules linked by a 1,4 glycosidic bond
351
Mass transport system
A transport system where substances are transported in a mass of fluid
352
mature mRNA
mRNA after the removal of introns and any other post-transcriptional changes to the per-mRNA, e.g:
- a tail (long chain of adenine nucleotides) added to the 3' end
- a cap (modified nucleotide) added to 5' end - aids binding of mRNA to ribosomes
BOTH help to stabilise mRNA and delay degradation in cytoplasm
353
Medulla
The lighter inner layer of the kidney made up of the loops of henle + part of collecting duct
354
Meiosis
Form of cell division where the nucleus divides twice (meiosis 1 and meiosis 2) resulting in a halving of the chromosome number and producing four haploid genetically different daughter cells from one diploid cell
355
Membrane
A selectively permeable barrier surrounding all cells and forming compartments within eukaryotic cells.
356
Membrane proteins
Protein components of cell-surface membranes
- extrinsic
- intrinsic
357
Meristematic tissue (meristems)
Tissue found at regions of growth in plants. Contains stem cells.
358
messenger (m) RNA
Short strand of RNA produced by transcription from the DNA template strand. It has a base sequence complementary to the DNA from which it is transcribed, except it has uracil (U) in place of thymine)
359
Metaphase
Second stage of mitosis when chromosomes line up at the meta phase plate, spindle attaches to chromatids at centromere
360
Methylation
The addition of methyl group
361
Micropropagation
The process of making very large numbers of genetically identical offspring from a single parent plant using tissue culture techniques. (plants)
362
Mitosis
Nuclear division stage in the mitotic phase of the cell cycle
363
Mitotic Phase
Period of cell division of the cycle . Consists of the stages mitosis (PMAT) and cytokinesis
364
Cytokinesis
The stage in mitotic phase when the cytoplasm divides. to produce two genetically identical diploid daughter cells. In animal cells, a cleavage furrow forms to divide the cell membrane. Usually begins in anaphase and ends in telophase. Its a separate process to mitosis
365
Mitochondrial DNA
DNA present within the matrix of mitochondria
366
Mitochondrial matrix
The part of the mitochondria enclosed by the inner mitochondrial membrane which contains enzymes for the Krebs cycle and the link reaction.
367
Monoclonal antibodies
Antibodies from a single clone of cells that are produced to target particular cells or chemicals in the body
368
Monoculture
The cultivation of a single crop in a given area
| - reducing the species biodiversity.
369
Monogenic inheritance
A characteristic inherited on a single gene
370
Monomers
Individual molecules that make up a polymer
371
Monosaccharide
A single sugar molecule
372
Monozygotic twins
Twins formed from a single fertilized egg
373
mRSA (methicillin-resistant Staphylococcus aureus)
A mutated strain of the bacterium Staphylococcus aureus that is resistant to the antibiotic, methicillin
374
Mucous membranes
Membranous linings of body tracts that secrete a sticky mucus
375
Multiple alleles
A gene with more than two possible alleles e.g: blood type
376
Multipotent
A stem cell that can only differentiate into a range of cell types within a certain type of tissue
377
Mutagens
Chemical or physical agent which causes mutation
378
Mutation
A change in the genetic material which may affect the phenotype of the organism
379
Myelin sheath
Membrane rich in lipid which surrounds the axon of some neurones, speeding up impulse transmission, produced by schwann cells.
380
Myofibril
Long cylindrical organelles found in muscle which are made of protein and specialised for contraction
381
Myogenic
Muscle which has its own intrinsic rhythm e.g. heart muscle
382
Satellite DNA
Short sequences of DNA that are repeated many times
383
Minisatellite
A sequence of 20-50 base pairs, repeated from 50 to several hundred times. Occurs at more than 1000 locations in the genome. Known as Variable number tandem repeats (VNTRs)
384
Microsatellite
A smaller region than VNTRs of just 2-4 base pairs that are repeated only 5-15 times. Always appear on the same positions on the chromosome and are known as Short tandem repeats (STRs)
385
NAD
A coenzyme found in all living cells involved in cellular respiration
386
NADP
A coenzyme which acts as a final electron acceptor in photosynthesis
387
Natural active immunity
Immunity which results from the response of the body to the invasion of a pathogen
388
Natural passive immunity
The immunity given to an infant mammal by the mother through the placenta and the colostrum
389
Natural selection
The process by which organisms best suited to their environment survive and reproduce, passing on their characteristics to their offspring through their genes. Over time, the proportion of the population possessing the advantageous adaptations increases. Over generations this leads to evolution as the favourable adaptations become more common in the population.
390
Nephrons
Tubules that make up the main functional structures of the kidneys.
391
Neurone
Specialised cell which transmits impulses in the form of action potentials.
392
Neurotransmitter
Chemical involved in communication across a synapse between adjacent neurones or a neurone and muscle cell e.g. acetylcholine
393
Nitrification
Conversion of ammonium compounds into nitrites (nitrosomonas) and nitrates (nitrobacter) through oxidation
394
Nitrile Hydratase
Enzyme used to convert acrylonitrile to acrylamide for use in the plastics industry
395
Nitrogen fixation
Conversion of nitrogen gas to ammonium compounds by nitrogen fixing bacteria azotobacter (soil) and rhizobium (root nodules in leguminous plants - symbiotic mutualistic relationship)
396
Non-competitive inhibitor
An inhibitor that binds to an enzyme at an allosteric site
397
Non-cyclic photophosphorylation
The synthesis of ATP and reduced NADP involving photosystems 1 and 2
398
Non-random sampling
An alternative sampling method to random sampling, where the sample is not chosen at random. It can be opportunistic, stratified or systematic.
399
Normal distribution
A distribution of continuous data where the mean, median, and mode have the same value, there is symmetry around the mean with most data points being close to the mean and fewer data points further away from the mean. When plotted produces a bell-shaped or normal distribution curve.
400
Nucleic acids
Large polymers formed from nucleotides. Contain the elements carbon, hydrogen, phosphorous, and oxygen. E.g: DNA + RNA
401
Nucleotides
The monomers used to form nucleic acids. Made up of a pentose monosaccharaide, a phosphate group and a nitrogenous base.
402
Obligate Aerobes
Organisms that can only respire aerobically E.g. mammals
403
Obligate Anaerobes
Organisms that cannot live in environments containing oxygen, mainly prokaryotes + some fungi
404
Open circulatory system
A circulatory system with a heat but few vessels to contain the transport medium, e.g. insects
405
Operculum
The bony flap covering the gills of bony fish. Part of the mechanism that maintains a constant flow of water over the gas exchange surfaces
406
Operon
A group of genes that are under the control of the same regulatory mechanism and are expressed at the same time
407
Opportunistic sampling
Sampling using the organisms that are conveniently available. The weakest form of sampling as it may not be representative of the population.
408
Opsonins
Chemicals that bind to pathogens and tag them so they are recognized more easily by phagocytes, e.g.antibodies
409
Organelle
Membrane-bound compartments with varying functions inside eukaryotic cells.
410
Ornithine cycle
A series of enzyme controlled reactions in the liver converting ammonia formed by deamination of amino acids into urea.
2 Ammonia + Carbon dioxide + 3 ATP = Urea + Water + 3 ADP
411
Osmoreceptors
Sensory receptors that respond to changes in the water potential of the blood
412
Osmoregulation
The balancing and control of the water potential of the blood
413
Osmosis
Diffusion of water through a partially permeable membrane down a water potential gradient. A passive process
414
Outbreeding
Breeding of distantly related organisms
415
Outer mitochondrial membrane
The membrane that separates the contents of the mitochondrion from the rest of the cell, creating a cellular compartment with ideal conditions for aerobic respiration
416
Oxaloacetate
Four carbon molecule present at the beginning of Krebs cycle that combines with acetyl coenzyme A to form citrate
417
Oxidation
Removal of electrons or hydrogen
418
Oxygen dissociation curve
Graph showing the relationship between oxygen and haemoglobin at different partial pressures of oxygen
419
Oxygenated blood
Blood that has passed through the gas exchange organs e.g. lungs, and his high in oxygen
420
Pandemic
When a communicable disease spreads rapidly to a lot of people across a number of countries
421
Partially permeable
Membrane that allows some substances to cross but not others
422
Passive transport
Transport that is a passive process (does not require energy) and does not use energy from cellular respiration
423
Pathogens
Microorganisms that cause disease
- Bacteria e.g. Tuberculosis (Mycobacterium tuberculosis + M.bovis, Bacterial Meningitis (Streptococcus pneumoniae), Ring rot in potatoes and tomatoes (Clavibacter michiganensis)
- Virus e.g. HIV/AIDS (retrovirus), Influenza, Tobacco Mosaic virus
- Protoctista e.g. Malaria (Plasmodium carried in female vector Anopheles mosquito), Potato/Tomato late blight (the oomycete - Phytophthora infestans)
- Fungi e.g. Black sigatoka (Mycosphaerella fijiensis), Ring worm, Athlete's foot (Tinia pedia)
424
Oomycete
Fungus like protoctista
425
Bacteria
Pathogen that produces toxins that can damage cell membranes, inactivate enzymes and interfere with metabolism. E.g TB, Bacterial meningitis and ring rot
426
Protoctista
Pathogen that does not insert new DNA but digest cells, replicate inside cell and burst out. E.g. malaria, potato/tomato late blight
427
Fungi
Pathogen that digests cells and destroys them E.g. black sigatoka, ring worm and athlete's foot
428
Virus
Pathogen that inserts new DNA into cells, takes over its cell metabolism and replicate inside cell then burst out. E.g. tobacco mosaic virus, influenza, HIV/Aids
429
Parasites
Organism that live on or in a host, harming it, it may cause disease but causes damage that allows a second infection, that also live part or all of their life in/on host.
430
Pelvis
The central chamber of the kidney where urine collects before passing out down the ureter
431
Penicillin
The first widely used, safe antibiotic, derived from a mould, Penicillium notatum
432
Penicillin acyclase
Enzymes used to make semi-synthetic penicillins from naturally produced penicillins.
433
Pentose monosaccharide
A monosaccharide composed of five carbons
434
Peptide bond
A bond formed between two amino acids
435
Peptides
Chains of two or more amino acid molecules
436
Peripheral nervous system (PNS)
Consists of all the neurones that connect the CNS to the rest of the body (motor and sensory)
437
Phagocytosis
Process by which white blood cells called phagocytes recognise non-self cells, engulf then digest them within a vesicle called a phagolysosome.
438
Phagosome
The vesicle in which a pathogen or damaged cell is engulfed by a phagocyte.
439
Pharming
The use of genetically modified animals to produce pharmaceuticals
440
Phenotype
Observable characteristics of an organism
441
Phloem
Plant transport tissue that carries the products of photosynthesis (assimilates) to all cells of the plant.
442
Phosphodiester bonds
Covalent bonds formed between the phosophate group of one nucelotide and the hydroxyl (OH) group of another.
443
Phospholipid bilayer
Arrangement of phospholipids found in cell membranes; the hydrophilic phosphate heads from both the inner and outer surface of a membrane, sandwiching the fatty acid tails to form a hydrophobic core.
444
Phosphorylation
The addition of a phosphate group to a molecule
445
Phospholipids
Modified triglycerides, where one fatty acid has been replaced with a phosphate group. 1 phosphate and two fatty acid chains
446
Photosynthesis
Synthesis of complex organic molecules using light
447
Photosystem
Protein complexes involved in the absorption of light and electron transfers in photosynthesis.
448
Phototropism
The growth response of plants to unilateral light
449
Phylogeny
The evolutionary relationships between organisms
450
Pigment
Molecules that absorb specific wavelengths of light
451
Pinocytosis
Endocytosis of liquid materials
452
Pioneer species
The first organisms to colonise an area E.g. algae and lichen
453
Plagioclimax
Stage in succession where artificial (human) or natural factors prevent the natural climax community from forming
454
Plasma
The main component of blood, a yellow fluid containing many dissolved substances (glucose, amino acids, mineral ions, hormones and large plasma proteins) and carrying blood cells, white blood cells and platelets
455
Plasma cells
B lymphocytes that produce about 2000 antibodies to a particular antigen every second and release them into the circulation.
456
Plasma membrane
All the cell surface membranes of cells, which have the same basic structure described by the fluid mosaic model.
457
Pluripotent
A stem cell that can differentiate into any type of cell, but not form a whole organism
458
Polymerase chain reaction (PCR)
A process by which a sample of DNA can be amplified using specific enzymes and temperature changes
1. Denaturation - temp 95 degrees Celsius, breaks hydrogen bonds between adjacent nucleotides leaving template single strands of exposed bases
2. DNA primer annealing - temp decrease to 52 degrees Celsius, short sections of DNA (primers) anneal to end of DNA fragments
3. Synthesis of DNA - temp increases 72 degrees Celsius taq polymerase (type of thermophilic DNA polymerase) optimum temp, binds to primers and transcribe along fragments adding bases building up complementary strands of DNA
459
Polymers
Long-chain molecules composed of linked (bonded) multiple individual molecules (monomers) in a repeating pattern.
460
Polymorphic allele
A gene with more than two possible alleles
461
Polypeptide
Chains of three or more amino acids
462
Polysaccharide
A polymer made up of many sugar monomers (monosaccharides)
463
Posterior pituitary gland
The posterior part of the pituitary gland in the brain where ADH is stored ready for release into the blood
464
Predation
The capturing of prey in order to sustain life
465
Preservation
Protection of an area by restricting or banning human use - so that the ecosystem is kept exactly as it is.
466
Primary immune response
The relatively slow production of a small number of the correct antibodies the first time a pathogen is encountered
467
Primary or pre mRNA
The mRNA transcribed from the DNA before any post-transcriptional regulation to remove introns etc.
468
Producer
Organism that converts light energy into chemical energy
469
Prokaryotes
Single-celled prokaryotic organisms from the kingdom Prokaryotae
470
Prokaryotic cells
Cells with no membrane-bound nucleus or organelles]
- Extremely small cells (less than 2 um diameter)
- Circular DNA
- No nucleus - DNA is free in cytoplasm
- Cell wall made of a polysaccharide, but not cellulose or chitin
- Few organelles and no membrane-bound organelles, e.g. no mitochondria
- Flagella, if present, made of the protein flagellin, arranged in a helix
- Small ribosomes (70s)
471
Eukaryotic cells
- Larger cells (about 10-100 um diameter)
- Linear DNA
- Nucleus present - DNA is inside nucleus
- No cell wall in animals, cellulose cell wall in plants, chitin cell wall in fungi
- Many organelles present + membrane-bound e.g. mitochondria
- Flagella, if present, made of microtubule proteins arranged in a '9 + 2' formation
- Larger ribosomes (80s)
472
Prophase
First stage of mitosis when chromatin condenses to form visible chromosomes and the nuclear envelope breaks down
473
Prosthetic group
Non-protein component of a conjugated protein E.g. haem group in haemoglobin
474
Proteases
Enzymes that catalyse the breakdown of proteins and peptides into amino acids
475
Proteins
One or more polypeptides arranged as a complex macromolecule
476
Proteomics
The study and amino acid sequencing of an organisms entire protein complement
477
Protista
Biological kingdom containing unicellular eukaryotes
478
Proximal convoluted tubule
The first twisted section of the nephron after the Bowman's capsule where many substances (glucose, amino acids, vitamins and some salts and some urea) are reabsorbed into the blood by active transport and facilitated diffusion
479
Purines
Big double-ringed, nitrogenous bases that form part of a nucleotide (Adenine and Guanine)
480
Purkyne fibres
Tissue that conducts the wave of excitation to the apex of the heart
481
Pyrimidines
Smaller single-ringed, nitrogenous bases that form part of a nucleotide (Thymine, Uracil and Cytosine)
482
Pyruvate
Three carbon product of glycolysis that feeds into Krebs cycle in the presence of oxygen
483
Quaternary structure
The association of two or more protein subunits
484
Random sampling
Sampling where each individual in the population has an equal likelihood of selection
485
Receptors
Extrinsic glycoproteins that bind chemical signals, triggering a response by the cell
486
Recessive allele
Version of a gene that will only be expressed if two copies of this allele are present in an organism
487
Recombinant
New combination of alleles/DNA from two sources
488
Recombinant chromatids
Chromatids with a combination of DNA from both homologous chromosomes, formed by crossing over and chiasmata in meiosis.
489
Recombination frequency
A measure of the amount of crossing over that has happened in meiosis it is the proportion of recombinant offspring resulting from a cross
Recombination frequency = number of recombinant offspring over total number of offspring
490
Reducing sugars
Saccharides (sugars) that donate electrons resulting in the reduction (gain of electrons) of another molecule
491
Reduction division
Cell division resulting in the production of haploid cells from a diploid cell; meiosis
492
Reflex action
Involuntary response to a sensory stimulus
- knee-jerk
- eye blinking
493
Regulatory gene
A gene that codes for proteins involved with DNA regulation
| E.g. regulatory gene (lacI) in lac operon that codes for repressor protein
494
Renal dialysis
A process where the functions of the kidney are carried out artificially to maintain the salt and water balance of the blood
495
Repolarisation
A change in potential difference from positive back to negative across the membrane of a neurone back to resting potential
496
Repressor protein
Protein synthesised by regulatory genes that binds to operator affecting the rate of transcription
497
Respiration
Breakdown of complex organic molecules linked to the synthesis of ATP
498
Respiratory quotitent
Ratio of carbon dioxide produced to oxygen used in respiration
RQ = CO2 produced over O2
499
Respiratory substrates
Organic molecules broken down in respiration
500
Residual volume
The volume of air that is left in the lungs after forced exhalation. It cannot be measured directly
501
Resolution
The shortest distance between two objects that are still seen as separate objects. The ability to see individual objects as separate entities.
502
Response
The way a body reacts to stimulus
503
Resting potential
The potential difference across a membrane of the axon of a neurone at rest, normally about -65mV to -70mV
504
Restriction endonucleases
Enzymes that chop a strand of DNA into small fragments
505
R-Groups
Variable groups on amino acids
506
ribonucleic acid (RNA)
Polynucleotide molecules involved in the copying and transfer of genetic information from DNA. The monomers are nucleotides consisting of a ribose sugar and one of four bases; uracil, cytosine, adenine and guanine
507
Ribose
The pentose monosaccharide present in RNA molecules
508
ribosomal (r) RNA
Form of RNA that makes up the ribosome
509
Ribulose bisphosphate
Five carbon molecule at the beginning of Calvin cycle
510
Ribulose bisphosphate carboxylase (RuBisCo)
Key enzyme involved in the first step of carbon fixation in photosynthesis
511
RNA polymerase
Enzyme that catalyses the formation of phosphodiester bonds between adjacent RNA nucleotides
512
Root hair cells
Cells found just behind the growing tip of a plant root that have long hair-like extensions that greatly increase the surface area available for the absorption of water and minerals from the soil
513
Root pressure
The active pumping of minerals into the xylem by root cells that produces a movement of water into the xylem by osmosis.
514
Saprophytic/saprotrophic
Organisms that acquire nutrients by absorption - mainly of decaying material
515
Sarcomere
Functional unit of myofibril
516
Scanning electron microscopy (SEM)
An electron microscope in which a beam of electrons is sent across the surface of a specimen and the reflected electrons are focused to produce a three-dimensional image of the specimen surface.
517
Secondary immune response
The relatively fast production of very large quantities of the correct antibodies the second time a pathogen is encountered as a result of immunological memory - the second stage of a specific immune response.
518
Seed bank
A store of genetic material from plants in the form of seeds
519
Selection pressure
Factors that affect an organism's chance of survival or reproductive success
520
Selective breeding
Selection of individuals for breeding with desirable characteristics
521
Selective toxicity
The ability to interfere with the metabolism of a pathogen without affecting the cells of the host
522
Selective reabsorption
The reabsorption of selected substances, i.e. those needed by the body, in the kidney tubules
523
Selectively permeable
Plasma membrane with protein channels that allow specific substances to cross only
524
Semi-conservative replication
DNA replication results in one old strand and one new strand present in each daughter DNA molecule
525
Sense strand
The strand of DNA that runs 5' to 3' and contains the genetic code for a protein
526
Sensory receptor
Specialised cell which detects a stimulus
527
Seral stages
The steps in succession
528
Sex linked genes
Genes carried on the sex chromosomes
529
Sliding filament model
Movement of actin and myosin filaments in relation to each other to cause contraction in muscles
530
Sieve plates
Areas between the cells of the phloem where the walls become perforated giving many gaps and a sieve-like appearance that allows the phloem contents to flow through
531
Sieve tube elements
The main cells of the phloem that have a greatly reduced living content and sieve plates between the cells
532
Simpson's Index of Biodiversity (D)
A measure of biodiversity between 0 and 1 that takes place into account both species richness and species evenness
533
Species richness
The number of different species living in a particular area
534
Species evenness
A comparison of the numbers of individuals of each species living in a community
535
Single circulatory system
A circulatory system where the blood flows through the heart and is pumped out to travel all around the body before returning to the heart. E.g: fish and annelid worms
536
Sinks (in plants)
Regions of a plant that require assimilates to supply their metabolic needs, e..g roots, fruits
537
Sino-atrial node (SAN)
Region of the heart that initiates a wave of excitation that triggers the contraction of the heart. The hearts natural pacemaker
538
Somatic cell gene therapy
Replacing a faulty gene with a healthy allele in affected somatic cells.
539
Somatic cell nuclear transfer
A method of producing a clone from an adult animal by transferring the nucleus from an adult cell to an enucleated egg cell and stimulating development.
540
Somatic nervous system
Part of the nervous system that is under conscious control
- myelinated
- connections to effectors only exists of one neurone
- cell bodies of the motor neurones are found in the CNS
- includes all sensory neurones and motor neurones that carry information to the skeletal muscles
541
Autonomic Nervous system (details)
- non-myelinated
- connections to effectors always consists of at least two neurones (which connects at a swelling called a ganglion)
- the cell bodies of motor neurones are found outside the CNS in the autonomic ganglia
- includes all the motor neurones that communicate with internal organs
- responsible for controlling most homeostatic processes
- controls all the activity of smooth muscle e.g. walls of arterioles and gut
- controls the heart rate
- controls the activity of exocrine glands e.g. salivary
542
Somatic motor pathway
motor neurone to skeletal muscle
543
Autonomic motor pathway
preganglionic neurone to autonomic ganglion (sympathetic) to motor neurone to smooth muscle inside organ
544
Smooth endoplasmic reticulum
Endoplasmic reticulum lacking ribosomes; the site of lipid and carbohydrate synthesis, and storage.
545
Sources (in plants)
Regions of a plant that produce assimilates e.g. glucose/sucrose by photosynthesis or from storage materials, e.g. leaves, storage organs
546
Spearman's rank correlation coefficient
A specific type of correlation test that compares the ranked orders of two data sets in order to consider their relationships
547
Specialised
Having particular structures to serve a specific function
548
Speciation
The formation of new species
- Allopatric (physical barrier making some members of a pop separated from the rest by a physical barrier making them geographically isolated)
- Sympatric (same habitat)
549
Species
The smallest and most specific taxonomic group
550
Specific immunity
Also known as active immunity or acquired immunity - the immune system 'remembers' an antigen after an initial response to subsequent encounters
551
Spiracles
Small openings along the thorax and abdomen of an insect that open and close to control the amount of air moving in and out of the gas exchange system and the level of water loss from the exchange surfaces.
552
Stabilising selection
Natural selection that favours the average phenotype
553
Stage graticule
A slide with a scale in micrometers (um) etched into it. Used to measure the size of a sample under a light microscope
554
Stains (staining)
Dyes used in microscopy sample preparation to increase contrast or identify specific components
555
Starch
A polysaccharide formed from alpha glucose molecules either joined to form amylose or amylopectin
556
Stem cells
Undifferentiated cells with the potential to differentiate into a variety of the specialised cell types of the organism
557
Stimulus
Detectable change in external or internal environment of an organism
558
Stomata
Pores in the surface of a leaf or stem that may be opened and closed by guard cells
559
Stratified sampling
Sampling where populations are divided into sub-groups (strata) based on a particular characteristic. A random sample is then taken from each of these strata proportional to its size.
560
Stroma
Fluid interior of chloroplasts containing enzymes controlling the carbon fixation reactions.
561
Structural genes
Genes that code for structural proteins or enzymes not involved in DNA regulation
562
Student's t-test
Statistical test used to compare the means of data values of two populations
563
Substrate
A substance used, or acted on, by another process or substance. For example a reactant in an enzyme-catalysed reaction
564
Substitution
A point mutation where one or more nucleotides are substituted for another in a DNA strand
565
Substrate level phosphorlyation
Synthesis of ATP by transfer of phosphate group from another molecule
- The production of ATP involving the transfer of a phosphate group from a short-lived, highly reactive intermediate such as creatine phosphate
566
Succession
The progressive replacement of one dominant type of species or community by another in an ecosystem, until a stable climax community is established
567
Sucrose
A dissacharide made up of a fructose and glucose monosaccharides
568
Summation
Build up of neurotransmitter in a synapse to sufficient levels to trigger an action potential
569
Sustainable development
Economic development that meets the needs of people today, without limiting the ability of future generations to meet their needs.
570
Sustainable resource
A renewable resource which is being economically exploited in such a way that it will not diminish or run out
571
Sympatric speciation
Speciation that occurs when there is no physical barrier between populations so occurs in the same habitat
572
Symplast
The continuous cytoplasm of living plant cells connected through the plasmodesmata
573
Symplast route
Movement of water and solutes through the cytoplasm of the cells via plasmodesmata by diffusion (passive)
574
Synapse
The junction (small gap) between two neurones, or a neurone and an effector. Consists of a synaptic bulb, synaptic cleft and post synaptic neurone. Important for:
- unidirectional
- removing low level summation
- nerve networks
- learning and memory
575
Synthetic biology
The design and construction of novel biological pathways, organisms or devices, or the redesign of existing natural biological systems
576
Systematic sampling
Different areas of a habitat are identified and sampled separately. Often carried out using a line or belt transect
577
Systole
The stage of the cardiac cycle in which the atria contract, followed by the ventricles, forcing blood out of the right side of the heart to the lungs and the left side of the heart to the body
578
T helper cells
T lymphocytes with CD4 receptors on their cell-surface membranes, which bind to antigens on antigen-presenting cells and produce interleukins, a type of cytokine
579
T killer cells
T lymphocytes that destroy pathogens carrying a specific antigen with perforin
580
T lymphocytes
Lymphocytes which mature in the thymus gland and that both stimulate the B lymphocytes and directly kill pathogens
581
T memory cells
T lymphocytes that live a long time and are part of the immunological memory
582
T regulatory cells
T lymphocytes that suppress and control the immune system, stopping the response once a pathogen has been destroyed and preventing an autoimmune response.
583
Tachycardia
An abnormally fast heart rhythm of over 100 beats per minute at rest
584
Tannins
Bitter tasting chemicals produced to prevent animals eating plant leaves; toxic to many insects
585
Target cells
Specific cells which hormones act on
586
Taxonomic group
The hierarchical groups of classification - domain, kingdoms, phylum, class, order, family, genus, species
587
Telophase
Fourth stage of mitosis when chromosomes assemble at the poles and the nuclear envelope reforms
588
Temperature coefficient (Q10)
A measure of how much the rate of a reaction increases with a 10 degrees Celsius temperature increase
589
Template strand
The antisense strand of DNA that acts as template during transcription so that the complementary RNA strand formed carries the same code for a protein as the DNA sense strand
590
Terpenoids
Chemicals found in plant leaves that may act as toxins to insects or fungi attacking the leaves. Compound forms essential oils that can be insect repellents.
591
Pheremones
Chemical that allows plants to communicate
592
Volatile Organic Compounds (VOCs)
Compounds that attracts predators (insects) for protection
593
Tertiary structure
Further folding of the secondary structure of proteins involving interactions between R-groups
- hydrogen bonds
- ionic bonds
- disulfide bridges
- hydrophobic and hydrophilic interactions
594
Test cross
A cross used to determine genotype, involving a backcross with a homozygous recessive parent
595
Thermoregulation
The maintenance of a relatively constant core temperature
596
Thin layer chromatography
A technique for separating different pigments through the rate at which they move across an inert surface carried by a solvent.
597
Thylakoid
Series of membranous compartments in a chloroplast that contain chlorophyll and molecules needed for light-dependent reaction.
598
Tidal volume
The volume of air which moves into and out of the lungs with each resting breath
599
Tissue
A collection of differentiated cells that have a specialised function or functions in an organism
600
Tissue fluid
The solution surrounding the cells of multicellular animals
601
Biotechnology
Applying biological organisms or enzymes to the synthesis, breakdown or transformation of materials in the service of people e.g. food, DNA manipulation and drugs
602
Tonoplast
Membrane forming a vacuole in a plant cell
603
Total lung capacity
The sum of the vital capacity and the residual volume
604
Totipotent
A stem cell that can differentiate into any type of cell and form a whole organism
605
Trachea
The main airway, supported by incomplete rings of cartilage, which carries warm moist air down from the nasal cavity into the chest
606
Tracheal fluid
Fluid found at the ends of the tracheoles in insects that helps control the surface area available for gas exchange and water loss
607
Transcription
The process of copying sections of DNA base sequence to produce smaller molecules of mRNA, which can be transported out of the nucleus via the nuclear pores to the site of protein synthesis
608
Transcription factors
Proteins that bind to DNA to switch genes on or off by affecting the rate of transcription (increase - activators or decrease - repressors)
609
transfer (t) RNA
Form of RNA that carries an amino acid specific to its anticodon to the correct position along mRNA during translation
610
Translation
The process by which the complementary code carried by mRNA is decoded by tRNA into a sequence of amino acids. This occurs at a ribosome
611
Translocation
The movement of organic solutes around a plant in the phloem
612
Transmission electron microscopy (TEM)
An electron microscope in which a beam of electrons is transmitted through a specimen and focused to produce an image
613
Transpiration
The loss of water vapour from the stems and leaves of a plant as a result of evaporation from cell surfaces inside the leaf and diffusion down a concentration gradient out through the stomata
614
Transpiration stream
The movement of water through a plant from the roots until it is lost by evaporation from the leaves
615
Transport system
The system that transports required substances around the body of an organism
616
Triglyceride
A lipid composed of one glycerol molecule and three fatty acids
617
Triose phosphate
A molecule that is an intermediate in both photosynthesis and respiration and acts as a starting material for the synthesis of carbohydrates, lipids and amino acids
618
Triplet code
The genetic code is a sequence of three nucleic acid bases, called a codon. Each codon codes for one amino acid.
619
Trophic level
Stage in a food chain
620
Tropism
A growth response by a plant in response to a unidirectional stimulus
- phototropism
- geotropism
- tropisms as response to environmental cues
621
Turgor
The pressure excreted by the cell-surface membrane against the cell wall in a plant cell
622
Ultrafiltration
The process by which blood plasma is filtered through the walls of the Bowman's capsule under pressure
623
Ultrastructure
The ultrastructure of a cell is those features which can be seen by using an electron microscope
- microtubule network
- vesicles
- nucleolus
- nucleus
- golgi apparatus
- cell-surface membrane
- cytosol
- ribosome
- centriole
- RER
- SER
- cytoskeleton
- secretory vesicles
- mitochondria
624
Undifferentiated
An unspecialised cell originating from mitosis or meiosis
625
Urea
Nitrogenous waste produced from the deamination of excess amino acids in the liver and ornithine cycle
626
Ureters
Tubes carrying urine from the kidneys to the bladder
627
Urethra
Tube carrying urine from the bladder to the outside of the body
628
Vaccine
A safe form of an antigen, which is injected into the bloodstream to provide artificial active immunity against a pathogen bearing the antigen
629
Vacuoles
Membranous sacs used to transport materials in the cell
630
Vascular bundle
The vascular system of herbaceous dicots, made up of xylem and phloem tissue + cortex
631
Vascular system
A system of transport vessels in animals or plants
632
Vector
A living or non-living factor that transmits a pathogen from one organism to another e.g. female malaria mosquito
633
Vector (in genetic modification)
A means of inserting DNA from one organisms into the cells of another organism
634
Vegetative propagation
The artificial production of natural clones for use in horticulture and agriculture
635
Ventilation rate
The total volume of air inhaled in one minute. Ventilation rate = tidal volume x breathing rate (per minute)
636
Vital capacity
Volume of air that can be breathed in when the strongest possible exhalation is followed by the deepest possible intake of breath
637
Vmax
Maximum initial velocity or rate of an enzyme-catalysed reaction
638
Water potential (trident symbol)
Measure of the quantity of water compared to solutes, measured as the pressure created by the water molecules in kilopascals (kPa)
639
Wild types
The allele that codes for the most common phenotype in a natural population
640
Xerophytes
Plants with adaptations that enable them to survive in dry habitats or habitats where water is in short supplying the environment E.g. marram grass, cacti
- thick waxy cuticle
- sunken stomata located in pits = reduced air movement + produces humid climate reducing transpiration
- reduced numbers of stomata
- reduced leaves
- thin needles reduce SA
- hairy leaves create humid microclimate
- curled leaves confines stomata in microenvironment of still, humid air
- leaf loss
- mass of widespread deep roots
641
Xylem
Plant transport tissue that carries water and dissolved minerals from the roots to the other parts of the plant as a result of physical forces
642
Zygote
The initial diploid cell formed when two gametes are joined by means of sexual reproduction. Earliest stage of embryonic development
