Paper 1: Advance Information Flashcards
(300 cards)
1
Q
Explain what happens in the activation of T helper cells
A
- Bacterium with antigen on surface is engulfed by macrophage.
- Macrophage presents antigens on its surface and becomes an APC.
- The APC eventually find the T helper cell with the complimentary CD4 receptor.
- Clonal expansion occurs and the T helper cell activates and divides into more T memory cells and T helper cells.
2
Q
How do hospitals minimise the selection pressure on bacteria?
A
- New patients screened on arrival
- antibiotics only used when needed and must complete the full course.
- Strict hygiene regimens
3
Q
What do the ribosomes of a prokaryotic cell do and what are they made up of?
A
They are smaller than in eukaryotic cell and make proteins.
4
Q
Where are ribosomes found?
A
Free in the cytoplasm or attached to the endoplasmic reticulum.
5
Q
How can biodiversity be compared to different habitats?
A
Using a formula to calculate an index of diversity
6
Q
What is the primary structure of protiens?
A
The sequence of amino acids in the polypeptide chain.
7
Q
What is a polypeptide?
A
More than 2 amino acids join together.
8
Q
How can our knowledge of dendrochronology tell us about past climates?
A
If a ring in a tree was bigger then the conditions for the tree were likely better
9
Q
What is allopatric speciation?
A
geographic isolation which results in speciation
10
Q
How are DNA fragments separated?
A
gel electrophoresis
11
Q
What is clonal expansion
A
T/B cells that are complementary to an antigen undergo rapid mitotic division to form many cloned cells.
12
Q
latency period
A
when HIV replication drops to a lower level and a person wont experience symptoms.
13
Q
How is new evidence analysed by the science community?
A
Scientific journals, peer review process and scientific conferences.
14
Q
What is the role of microorganisms in the decomposition of organic matter and the recycling of carbon?
A
Microorganisms use the corpse as a food source with energy being released through aerobic and anaerobic respiration. Carbon dioxide is released into the atmosphere by the respiring decomposers.
15
Q
lysis
A
the bursting of a cell
16
Q
What does ‘translation’ mean in terms of biology?
A
Turning the sequence of bases in the genetic code into a sequence of amino acids.
17
Q
What happens in the 3 stages of cycle 1 of a PCR?
A
- -DNA separates into two strands
- -Primers (small pieces of DNA with florescent markers) attach at the start of the STR repeated sequence
- -DNA polymerase attach. Nucleotides are added, extending the DNA from the primer. The STR repeated sequence and DNA adjacent is replicated.
18
Q
What happens in the calvin cycle
A
- CO2 combines with 5C compound RuBP and is catalysed by Rubisco
- The 6C compound formed is unstable so breaks down into 2 GP molecules
- GP is reduced using the hydrogen from reduced NADP and energy stored in ATP into GALP
- 2/12 GALPs formed create a 6C
- The remaining 10GALPs are involved in the recreation of RuBP. They rearange to form 6 5C compounds which are then phosphorylated using ATP to form RuBP.
19
Q
What are the two types of enzymes?
A
Intracellular (catalyse reactions inside cells) or extracellular (produced and secreted by cells that catalyse reactions outside cells)
20
Q
What is the role of thylakoid space in a chloroplast? and what does it contain?
A
contains enzymes for photolysis
21
Q
What is the role of a starch grain in a chloroplast?
A
stores the products of photosynthesis
22
Q
What is an example of a globular protein?
A
Eg. haemoglobin made up of four polypeptide chains. It carries oxygen around the body in the blood. Its soluble so it can be easily transported in the blood. It has haem groups that bind to oxygen.
23
Q
What does a mononucleotide look like?
A
24
Q
What are the possible effects of climate change?
A
changing rainfall patterns and changing seasonal cycles
25
What are the 4 methods proteomics and genomics?
DNA Hybridisation, DNA profiling, DNA and protein sequencing and DNA molecular clocks
26
What assumptions are made when we extrapolate
we have enough data to establish the trend accurately and that present trends continue
27
How does infection of TB occur
when droplets containing the bacteria are inhaled into the lungs
28
what are exons
coding regions
29
What is the cell wall and what is its role?
supports the cell made of a glycoprotein
30
What are eukaryotic cells?
They are complex and include all animal and plant cells.
31
What is thymine replaced with in RNA?
Uracil
32
How does the concentration of the enzymes effect the rate of reaction?
The more enzymes there are the more active sites are present and therefore the more likely a substrate molecule is to collide with an active site and form an enzyme substrate complex.
33
What is the lock and key model?
Substrate fits into the enzyme the same way a key fits into a lock.
34
What are introns
non-coding regions
35
What is the formula to calculate index of diversity?
D= N(N-1) / E\*n(n-1)
1. \*E = sum of
2. \*N total number of all species
3. \*n total number of one species
36
How can genetic profiling be used to identify paternity?
Offspring inherit one STR from each parent.
37
What is the structure of A and G?
They have a 2 ring structure
38
What is a monomer?
Amino acids
39
What is the quaternary structure?
Some proteins made of several different polypeptide chains held together by bonds. The quaternary structure is the way these polypeptide chains are assembled together.
40
What are immunoglobulins?
antibodies
41
What are the initial symptoms of TB?
Fever, general weakness and severe coughing caused by inflammation of the lungs.
42
why might these models have limitations
Limited data, limited knowledge, changing trends, limitations of computers and failure to include all factors
43
What is the first sign of decomposition
putrefaction when the abdomen turns green
44
What is the function of the Golgi apparatus?
It processes and packages new lipids and proteins. It also makes lysosomes.
45
What bonds hold together the secondary structure?
Hydrogen bonds
46
How does stomach acid protect the body?
kills bacteria ingested
47
What is speciation?
The development of new species.
48
Habitat
Place where an organism lives
49
What is the sequence of repeated bases in introns know as?
short tandem repeats or satellites
50
What is the role of the stroma in a chloroplast?
light independent reaction occurs here
51
What is primary succession?
when there has never been a community before
52
What is the definition for genotype
The alleles a person has eg BB, Bb or bb
53
What is the rough endoplasmic reticulum
A system of membranes enclosing a fluid filled space. The surface is covered with ribosomes.
54
What is the theory of the evolutionary race?
pathogens evolve adaptations that enable them to survive and reproduce.
55
Describe the structure of an enzyme
Enzymes have an active site, which has a specific shape. The active side is the part of the enzyme where the substrate molecules bind to.
56
What factors effect post mortem cooling
Body size, body position, clothing, air movement, humidity and temperature of suroundings.
57
What are the 4 non specific immune system responses?
Lysozyme, inflammation, phagocytosis and antimicrobial proteins
58
What is the DNA coding strand also known as?
The sense strand
59
What bonds hold together amino acids?
Peptide bonds
60
How does natural selection lead to adaptation and evolution? (6 marker)
1. **Mutations** can introduce new alleles into a population, so individuals within a population show variation in their phenotypes. Some of these alleles determine characteristics that can make the individual more likely to survive.
2. **Selection pressures** such as predation, disease and competition create a struggle for survival.
3. Individuals **without the advantageous allele don't survive**. This means there are fewer individuals and less competition for resources.
4. Individuals with the **advantageous allele** are **more likely to survive** and reproduce and **pass on** the advantageous allele.
5. **Over time** the number of individuals with the advantageous allele **increases**.
6. Over generations this leads to **evolution** as the **frequency** of the advantageous alleles in the population **increases** and the favourable adaptation becomes **more common**.
61
Why does intense heat slow down decomposition
As the enzymes involved in autolysis become denatured.
62
What are examples of how enzymes catalyse metabolic reactions?
* At a **cellular level** eg respiration
* For the **organism as a whole** eg digestion
63
What happens in each cycle of a PCR?
The process is repeated producing copies that are just the STR sequence fragment.
64
What is the function of the mitochondrion?
The site of the aerobic respiration, where ATP is produced. They're found in large numbers in cells that are very active and require lots of energy.
65
What does the smooth ER do?
Synthesises and processes lipids.
66
What is the nature of the genetic code?
**Triplet code**- each adjacent group of 3 bases codes for an amino acid.
**Non-overlapping**- each triplet code is adjacent.
**Degenerate**- Several triplets can code for the same amino acid.
67
How is energy released from ATP in water?
The 3rd phosphate ion becomes hydrated forming bonds with the surrounding water molecules. In which lots of energy is released.
68
What is the structure of ATP
adenine, ribose, 3 phosphate groups
69
What is the function of the ribosome?
The site where proteins are made.
70
What are the two reasons why an enzyme substrate complex lowers the activation energy?
If two substrate molecules need to be joined, being attached to the enzyme holds them close together, reducing any repulsion so they can bond more easily.
If the enzyme is catalysing a breakdown reaction, fitting into the active site puts a strain on bonds in the substrate, so the substrate molecule breaks up more easily.
71
What is a lysosome?
A round organelle surrounded by a membrane, with no clear internal structure.
72
What is an example of artificial passive immunity?
When antibodies are injected into the body
73
What do bacteria have that viruses do not have?
plasma membrane, cytoplasm and ribosomes
74
What bonds hold together the quaternary structure?
Determined by the tertiary structure of the individual polypeptide chains being bonded together. So can be influenced by all mentioned bonds.
75
When does speciation occur?
When populations of the same species become reproductively isolated.
76
What is an example of natural active immunity?
Being exposed to or getting the disease
77
When can body temperature be useful in determining time of death?
during the first 24 hours
78
What is the role of a granum in a chloroplast?
contains a stack of thylakoids
79
What is used in the light independent reactions
carbon dioxide
80
Mutualism
A relationship between two species in which both species benefit
81
Endemism
When a species is unique to a single place and isn't naturally found anywhere else.
82
What is the golgi apparatus?
A group of fluid filled membrane bound, flattened sacs. Vesicles are often seen at the edges of the sacs.
83
antigens
Foreign material that invades the body
84
When are 2 species able to share the same habitat
Only if they occupy different niches
85
allele
Different version of the a gene which codes for a different version of the same gene
86
What does the pili of a prokaryotic cell do and what is it made up of?
Pili help prokaryotes stick to other cells and can be used in the transfer of genetic material between cells.
87
What are enzymes?
They speed up chemical reaction acting as biological catalysts.
88
What would happen if a mutation occurs in the gene that codes for the protein that is the enzyme?
The primary structure will be different and that could result in the tertiary structure being different.
89
Why do scientists evaluate new data?
To check that the experiments or studies were designed properly and that the conclusions were fair.
90
How are the fragments of DNA created?
Restriction enzymes are used. They will only cut up DNA at specific base sequences. They cut away the STR from the DNA.
91
What are dipeptides?
When 2 amino acids join together.
92
Why is methane harmful?
it absorbs more infrared radiation than a molecule f CO2 does
93
What are ribosomes composed of?
2 subunits: a smaller and larger subunit. The larger subunit contains two tRNA binding sites and the mRNA attaches to the smaller subunit.
94
What effect does temperature have on decomposition?
Warm temps speed it up and lower temperatures slow down decomposition.
95
How does photosynthesis impact the carbon cycle?
The reduction of CO2 into organic substance and the release of oxygen as a waste product
96
How does inflammation occur?
The damaged white blood cells release special chemicals eg histamine. Causing the arterioles in the area to dilate and increasing the permeability of the capillaries. Plasma fluid, white blood cells and antibodies leak from the blood into the tissue causing oedema.
97
WHat is evolution
change in allele frequency over time
98
What are fibrous proteins? and what are their features?
Long, insoluble polypeptide chains that are tightly coiled round each other to form a rope shape.
The chains are held together by lots of bonds which makes the proteins strong.
Because they're strong they can be found in supportive tissue.
99
Name 5 abiotic factors that effect the numbers and distribution of organisms
Solar energy input, climate, oxygen concentration, pollution catastrophe.
100
what might cause the climax community to change
unless the conditions in the habitat changes the climax community is stable
101
What is net primary productivity?
gross primary productivity - respiration
102
How can biodiversity be measured within a habitat?
Using species richness
103
What does the cell wall of a prokaryotic cell do and what is it made up of?
Supports the cell and prevents it from changing shape. Its made of a polymer called murein. Murein is a glycoprotein (a protein with a carbohydrate attached)
104
What 5 biotic factors effect the numbers and distribution of organisms
competition for resources, grazing, predation, disease and parasitism mutualism
105
Heterozygote
Bb
106
What is the secondary structure of proteins?
The polypeptide chain doesn't remain flat and straight. Hydrogen bonds form between the amino acids in the chain. This makes it automatically coil into an alpha helix or a beta pleated sheet.
107
What are the 8 categories in the classification hierarchy?
* Domain
* Kingdom
* Phylum
* Class
* Order
* Family
* Genus
* Species
108
Why is the arrangement of the DNA double helix the way it is?
The hydrophilic phosphate groups are on the outside of the molecule and the hydrophobic bases lie within the molecule.
109
How does a protein's primary structure determine its 3D structure and properties?
The amino acid sequence of a protein determines what bonds will form and how the protein will fold up into its 3D structure.
The 3D structure of a protein relates to its properties. Its properties relate to its function in the body.
110
why does the body turn greenish after death?
The formation of sulfhaemoglobin in the blood
111
Give examples of physiological adaptations
Brown bears hibernate- they lower their rate of metabolism over winter. This conserves energy, so they don't have to look for food in the months when its scarce.
Some bacteria produce antibiotics- these kill other species of bacteria in the area so that means there's less competition.
112
How does the skin protect the body?
tough physical barrier consisting of keratin
113
What happens once the temperature becomes too high?
The shape of its active site is lost and the enzyme substrate complex no longer forms as it is denatured.
114
What is a ribosome?
* A very small organelle that either floats free in the cytoplasm or is attached to the rough endoplasmic reticulum.
* Its made up of proteins and RNA.
* Its not surrounded by a membrane.
115
Where are B cells produced?
bone marrow
116
What are physiological adaptations?
Processes inside an organisms body that increase the chance of survival.
117
Understand how the … of multicellular organisms are organised into …., and …… into …… and …….. into ……..
Cells tissues tissues organs organs systems
118
What bonds hold together the primary structure?
Peptide bonds
119
What is a prokaryotic cell made up of?
1. Cell wall
2. Capsule
3. Plasmid
4. Flagellum
5. Pili
6. Ribosomes
7. Mesosomes
8. Circular DNA
120
What is it called when ADP and phosphate join together?
Phosphorylation
121
Autolysis
When the body's own enzymes, from the digestive tract and from lysosomes, break down cells.
122
When does HIV become AIDS?
when the CD4 (T helper cell) count goes below 200
123
How can one gene give rise to more than one protein?
1. Through post transcriptional changes to mRNA.
2. The introns are removed leaving only the exons. This is mRNA.
3. Before this it is called pre-mRNA when introns were still present.
4. Once the introns are removed the exons can be spliced in many different ways leading to more than one protein.
124
What does the equation p2 + 2pq + q2 = 1 stand for?
**p2 =** the frequency of the homozygous dominant genotype
**2pq =** the frequency of the heterozygous genotype
**q2 =** the frequency of the homozygous recessive genotype.
125
What is the impact of a mutation?
The order of DNA bases in a gene determines the order of amino acids in a particular protein. If a mutation in a gene, the primary structure (the sequence of amino acids) could be altered. Which could change the final 3D shape of the protein so it doesn't work properly.
126
What is the role of the inner membrane in a chloroplast?
Regulate the passage of substances
127
What do mesosomes of a prokaryotic cell do and what are they made up of?
Mesosomes are inward folds in the plasma membrane. They are believed to be involved in cellular processes.
128
What are globular proteins? and what are their features?
They are round and compact proteins made up of multiple polypeptide chains.
The chains are coiled up so that hydrophilic parts of the chain are on the outside of the molecule and hydrophobic are on the inside..
This makes the proteins soluble so they're easily transported in fluids.
129
What is proteomics
Study of proteins
130
What are mesosomes?
folds in the cell membrane
131
What does a lysosome do?
Contains **digestive enzymes**. These are kept separate from the cytoplasm by the surrounding membrane and can be used to **digest invading cells** or to **breakdown worn out components** of the cell.
132
What are prokaryotic cells
They are smaller and simpler eg bacteria
133
Why is it though that increased CO2 levels cause global warming?
There is a strong correlation between temperature and carbon dioxide concentration
134
Describe the process of DNA replication
1. Enzyme **DNA helicase** **breaks** the **hydrogen** bonds between bases on the two polynucleotide strands. This makes the helix **unwind** to form two single strands.
2. Each **original single strand** acts as a **template** for a new strand. Complementary base pairing means that **free floating DNA nucleotides** are attracted to their **complementary** exposed **bases** on each original template strand.
3. **Condensation reaction** join the nucleotides of the new strands together- **catalysed** by the enzyme **DNA polymerase.** **Hydrogen** bonds form between the bases on the original and new strands.
4. Each **new DNA molecule** contains **one** strand from the **original** DNA molecule and **one new** strand.
135
What 2 factors can we do to help maintain the balance?
Sustainable resources including biofuels and reforestation
136
What are the two main types of lymphocytes?
T cells and B cells
137
What temperature do the 3 stages of a PCR occur at?
95C, 55C and 70C
138
What are bacteriostatic antibiotics?
Bacteriostatic antibiotics inhibit the growth of bacteria through stopping protein synthesis and production of nucleic acids so bacteria cant divide and grow.
139
What are flagellum and what is their role?
Long hair like structure that rotates To make bacterium move.
140
What bonds hold the peptide chains of a T cell?
Disulphide bonds
141
Species diversity
The number of different species and the abundance of each species in an area.
142
How do introns help scientists create a unique DNA profile?
they are unlikely to have the same combination of STRs with the same number of repeats within.
143
How does HIV replicate?
1. HIV surface protein binds to cell receptors. The virus envelope fuses with cell surface membrane.
2. The virus uses the enzyme reverse transcriptase to turn the HIVs RNA into DNA.
3. Integrase inserts virus DNA into host DNA.
4. The cells natural process of protein synthesis and host cell enzymes are used to make viral proteins from the viral DNA found within the human DNA.
5. The viral proteins are assembled into new viruses which bud from the cell and go to infect other cells.
144
What are the 2 sub-definitions of biodiversity?
Species diversity
Genetic diversity
145
What are the products of the light independent reaction used for?
1. They are used by plants and animals in respiration
2. Synthesis of new biological molecules eg polysaccharides, amino acids, lipids and nucleic acids.
146
What is the function of the nucleus
Controls the cells activities (by controlling the transcription of DNA) DNA contains instructions to make proteins. The pores allow substances to move between the nucleus and the cytoplasm.
147
Why do different characteristics become more common of different sides of the physical barrier?
Conditions on either side of the barrier will be different as there might be a different climate on each sides.
148
What does the capsule of a prokaryotic cell do and what is it made up of?
Made up of secreted slime it helps to protect the bacteria from attack by cells of the immune system.
149
What are bactericidal antibiotics
They kill bacteria by destroying their cell wall and thus causing them to burst (lysis)
150
What is the mitochondrion?
They're usually oval-shaped. They have a double membrane- the inner one is folded to form structures called cristae. Inside the matrix, which contains enzymes involved in respiration.
151
Explain the stages of the light dependant reaction
#NAME?
152
What is an example of a fibrous protein?
e.g. Collagen which is a strong fibrous protein that forms connective tissue in animals.
153
How does biomass impact the carbon cycle?
Plant material accounts for the majority of photosynthesis in the world
154
Succession
Process by which an ecosystem changes over time. The biotic conditions change as the abiotic conditions change.
155
What happens if two species try to occupy the same niche?
They will compete with each other. One species will be more successful than the other until only one species is left.
156
What is deflected succession?
when human activity causes a community to remain stable because it prevents succession from running its course
157
How might climate change impact the development and life cycle of animals
If environmental cues trigger their behaviour or development. Spawning and hatching and growth rates are most likely to be effected.
158
Population
members of the same species that occupy the same area
159
Where does the light dependent reaction take place?
Thylakoid membranes
160
What are the first organism to colonise bore surfaces
lichen
161
What impact of the effects of climate change might it have on plants and animals
distribution of species, altered development and life cycles
162
How do you calculate biodiversity using the heterozygosity index?
Number of heterozygotes / number of individuals in the population
163
Genetic diversity
The variation of alleles within a species (or a population of a species)
164
What bond holds together adjoining nucleotides via the sugar (ribose or deoxyribose) and the phosphate?
phosphodiester bonds
165
How many hydrogen bonds does A and T have?
2 hydrogen bonds
166
What is the centriole?
Small, hollow cylinders made of microtubules (tiny protein cylinders) Found in animals, but only some plant.
167
How many hydrogen bonds do C and G have?
3 hydrogen bonds
168
Where is DNA in bacteria?
free floating in the cytoplasm
169
How does gut and skin flora protect the body?
natural bacterial flora competes with pathogens for food and space.
170
Why is an enzymes primary structure so important?
As the enzymes tertiary structure is determined by the primary structure. And the tertiary structure determines the enzymes active site which determines if the complementary substrate will fit into the active site.
171
What is the sequence of events during rigor mortis?
1 Muscles become starved of oxygen and oxygen dependant reactions stop 2 Respiration of the cells becomes anaerobic and produces lactic acid 3 pH of cell falls, inhibiting enzymes and thus inhibiting anaerobic respiration 4 ATP needed for muscle contraction is no longer produced so bonds between muscles become fixed 5 proteins can no longer move over one another so the muscles and joins become fixed.
172
How is a DNA profile made?
-A sample of DNA is obtained -Fragments of different lengths are created through cutting up the DNA -The fragments are separated and visualised -Then the profile is compared to another
173
phagocytosis
when phagocytes engulf and destroy antigens.
174
Why are enzymes highly specific?
Due to their tertiary structure
175
What is the definition for phenotype
The characteristics displayed by an organism eg brown eyes
176
What is the basic structure of an amino acid? and draw one
177
What types of errors can occur during DNA replication?
1. Substitution
2. Deletion
3. Insertion
4. Duplication
5. Inversion
178
what is a dominant species of a community?
the one that exerts an overriding influence over the rest of the plants etc. sometimes there is more than one and they are often the most abundant species.
179
which is the most potent greenhouse gas
methane
180
What is sympatric speciation?
a species evolves into a new species without a physical barrier
181
What has happened to biodiversity over time?
Over time the variety of life has become extensive but it is now being threatened by human activity.
182
what is often a feature of pioneer species?
seeds widely dispersed by wind, rapid growth, short life cycle and abundant seed production.
183
Explain the process in which proteins are transported in cells?
1. Proteins are made at the ribosomes on the rough ER.
2. New proteins produced at the rough ER are folded and processed in the rough ER.
3. The proteins are then transported from the ER to the Golgi apparatus in vesicles.
4. At the Golgi apparatus, the proteins may undergo further processing (further modification)
1. The proteins enter more vesicles to be transported around the cell.
184
What are the 2 factors likely responsible for the carbon cycle not being in balance?
combustion of fossil fuels and deforestation
185
what curve does the falling of body temperature follow?
Sigmoid curve
186
What is the basic structure of mononucleotides?
Deoxyribose or ribose linked to a phosphate and a base, including thymine, uracil, cytosine, adenine or guanine.
187
What happens if 2 species live in the same habitat and have exactly the same ecological niche
They will compete until the better adapted of the two outcompetes the other and excludes it from the habitat.
188
What is the role of the outer membrane in a chloroplast?
permeable to CO2 and H2O
189
How do you calculate net primary productivity
NPP = GPP - Plant Respiration
190
Give examples of anatomical adaptations
Otters have a streamlined shape making it easier to glide through the water. This makes it easier for them to catch prey and escape predators, increasing their chance of survival.
Whales have thick layer of blubber which helps keep them warm in the cold sea. This increases their chance of survival in places where their food is found.
191
What bonds hold together the tertiary structure?
1. **Ionic**- attractions between +ve and -ve charges.
2. **Disulfide bonds-** When two molecules of the amino acid cystine come close together, the sulfur atom in one cystine bonds to the other sulfur.
3. **Hydrophilic** and **hydrophobic** interactions
4. **Hydrogen** bonds
192
What is an example of natural passive immunity?
the crossing of mother's antibodies through the placenta and/or breast milk
193
What are plasmids and what is their role?
Small loops of DNA that aren't part of the chromosome.
194
What are mutations?
Changes to the base sequence of DNA
195
How is DNA obtained?
-Tissue sample is broken down in a buffer solution -The small suspended particles inc DNA are separated from the rest of the cell debris -Protease enzymes are incubated with the suspension to remove proteins -cold ethanol is added to precipitate out the DNA -The DNA is then washed in a buffer solution multiple times
196
What is a species?
A group of similar organisms that can reproduce to give fertile offspring.
197
What is the tertiary structure of proteins?
Coiled or folded chain of amino acids are coiled or folded further. More bonds form between different parts of the polypeptide chain, including hydrogen bonds and ionic bonds. Disulphide bonds can also form.
Proteins made of a single polypeptide chain, the tertiary structure forms their final 3D structure.
198
How do lysozymes protect against pathogens?
found in tears they kill bacteria by breaking down their cell walls. Also found in saliva and nasal secretion.
199
What happens once TB is in the lungs?
Bacteria is taken up by a phagocyte. Bacteria survive and replicate inside phagocytes. The infected phagocytes are sealed off in the lungs in tubercles. When in tubercles the bacteria is dormant and shows no obvious symptoms. The dormant bacteria might later become active and overcome the immune system. Reactivation is more likely in people with a weakened immune system.
200
What does the rough ER do?
Folds and processes proteins that have been made at the ribosomes.
201
What are the two ways TB kills a person?
In the lungs- respiratory failure If it spreads- organ failure
202
What does the flagellum of a prokaryotic cell do and what is it made up of?
Long hair like structure that rotates to make the prokaryotic cell move. Not all prokaryotes have a flagellum. Some have more than one.
203
What does the Hardy Weinberg equation predict? and under what conditions?
That the frequency of alleles in a population wont change from one generation to the next.
But it has to be a large population where there is no immigration, emigration ,mutations or natural selection. There also needs to be random mating.
204
How long does methane stay in the atmosphere?
it only stays in the atmosphere for 12 years before it reacts with oxygen to form CO2 and water
205
What are behavioural adaptations?
Ways an organisms acts that increase its chance of survival.
206
How else might a population become reproductively isolated?
Geographical isolation or random mutations that introduce new alleles into the population.
207
What are anatomical adaptations?
Structural features that increase an organisms chance of survival.
208
What is the classification of organisms based off of?
Their phenotypes, genotypes and how related they are.
209
What does the plasmid of a prokaryotic cell do and what is it made up of?
Plasmids are small loops of DNA and contain genes for things like anti-biotic resistance. They are not always present and some bacteria contain several.
210
What is the definition for gene?
A sequence of bases on a DNA molecule that codes for a protein, which results in a characteristic.
211
What is an organisms niche?
An organism's interactions with other living organisms and its interaction with the non living environment.
212
Why do reactions occur in enzymes slowly at low temperatures?
Enzymes and substrate have low kinetic energy so move slowly and do not collide often
213
What is the definition for recessive
An allele whose characteristic only appears in the phenotype if two copies are present.
214
How do enzymes speed up the rate of reaction
They lower the activation energy.
215
why do peat bogs highlight a changing climate?
peat is the accumulation of partially decayed organic matter. Pollen can be used to reconstruct the past climates.
216
How might climate change impact the distribution of species?
Some species may benefit from the change in climate and become dominant while others may be lost due to competition.
217
Ecosystem
the interaction between living organisms and the environment in a given area.
218
What is the impact on plants if enzymes denature
Higher temp and lower soil moisture as the enzymes denature
219
What is CF caused by? and what happens as a result?
* A mutation in the gene that codes for the CFTR protein.
* CFTR is a channel protein. It transports chloride ions out of the cell and into the mucus- this causes water to move into the mucus by osmosis, which makes mucus watery.
* Mutant CFTR protein is much less efficient at transporting chloride ions our of the cell so less water moves out by osmosis. This makes the mucus of people with CF abnormally thick and sticky.
* The thick and sticky mucus causes problems in the respiratory, digestive and reproductive systems.
220
How are global trends predicted?
Extrapolation- extending the line
221
How might climate change impact the development of plants?
For plants photosynthesis may initially be faster but eventually enzymes will no longer be at optimum and start to denature.
222
What does the circular DNA of a prokaryotic cell do and what is it made up of?
They are one long coiled up strand and are not attached to any histone proteins.
223
What does the equation p + q = 1 stand for?
p = the frequency of the dominant allele
q = the frequency of the recessive allele
224
Describe the process of translation of DNA
1. mRNA attaches to a ribosome and tRNA molecules carry amino acids to the ribosome.
2. A tRNA molecule with an anticodon that's complementary to the start codon on the mRNA attaches itself to the mRNA by complementary base pairing.
3. A second tRNA molecule attaches itself to the next codon on the mRNA in the same way.
4. The two amino acids attached to the tRNA molecule are then joined together by a peptide bond. The first tRNA molecule moves away, leaving its amino acid behind.
5. The ribosome moves along to the next codon.
6. A third tRNA molecule binds to that codon on the mRNA. Its amino acid binds to the first two and the second tRNA molecule moves away.
7. This process continues, producing a chain of linked amino acids (a polypeptide chain) until there's a stop codon on the mRNA molecule.
8. The polypeptide chain moves away from the ribosome and translation is complete.
225
What is the role of thylakoid membranes in a chloroplast?
contains chlorophyll and electron carriers and is involved in light dependant reactions
226
How does using sustainable resources help manage the conflict between human needs and conservation?
They are renewable and carbon dioxide neutral
227
Where are T cells produced?
thymus
228
How do you produce a DNA profile?
-Double stranded DNA + restriction enzymes and the DNA is cut into fragments - Fragments of double stranded DNA are loaded into the wells of agarose gel in a tank -Negatively charged DNA moves towards the positive electrode and the fragments separate into invisible bands. -DNA transferred to a nylon membrane. -Membrane placed in bag with DNA probe . -Probe binds to fragments with a complimentary sequence -If DNA probe is radio active x-ray is used. If florescent, it is viewed using UV light.
229
What are the 3 ways the body is protected from infection?
Skin, stomach acid, and gut and skin flora.
230
What are the three domains?
Bacteria, Archaea and Eukaryota
231
genome
all the DNA in a cell (all the genes)
232
What is the definition for dominant
An alleles who's characteristic appears in the phenotype even when there's only one copy.
233
What alters the tertiary structure of an enzyme?
pH or temperature
234
How do antimicrobial proteins provide a defence against pathogens?
They diffuse into the surrounding cells where it prevents microbes from multiplying. It inhibits microbial protein synthesis.
235
How does reforestation help manage the conflict between human needs and conservation?
Newly planted trees are rapidly growing and photosynthesising with little respiration so they are net absorbers.
236
What is it called when ADP and phosphate break apart?
Hydrolysis
237
What happens in colonisation
pioneer species colonise as they are the only organisms that can cope with extreme temperatures, lack of soil, water and nutrients.
238
What is the equation for photosynthesis?
6CO2 + 6H2O ------\> C6H12O6 + 6O2
239
Homozygote
BB or bb
240
What can influence conclusions about controversial issues?
They can be impacted by who is reaching those conclusions
241
Biodiversity
The variety of living organisms in an area
242
Why is pollen useful
each plant has a distinctive type of pollen and pollen has a tough outer layer and are produced in vast amounts
243
What causes changes in allele frequencies?
Mutations will take place independently and different characteristics will be advantageous, so the allele frequencies will lead to changes in each population.
244
What is gross primary productivity?
The rate at which energy is incorporated into organic molecules by an ecosystem
245
What do pioneer species do?
they start to break up the rock surface which allows organic matter to accumulate, allowing a new species to join
246
What is the template strand also known as?
The antisense strand
247
What reaction holds together polypeptides and when is this reversed?
Condensation reaction forms the bonds holding the amino acids together and the bonds are hydrolysed during digestion.
248
What is it called where the rate of reaction is highest?
Optimum temperature
249
Describe the process of transcription?
1. DNA unwinds and H bonds are broken
2. Coding strand used for mRNA synthesis
3. RNA polymerase used to join RNA nucleotides
4. Complementary base pairing A with U not T
250
What kills a person with AIDs?
Opportunistic infections
251
What can enzymes affect?
**Structures** in an organism eg production of collagen and **functions** eg respiration
252
What is the definition for an allele
A different version version of a gene
253
What is the structure of C and T
They have 1 ring
254
What is evolution?
The change in allele frequency
255
What is a gene?
A sequence of bases on a DNA molecule that code for a sequence of amino acids on a polypeptide chain.
256
Explain the role of T killer cells
A bacterium infects cell of host. The cell presents the antigen and becomes an APC. T killer cell with a complimentary receptor binds to the APC. Cytokines stimulate the differentiation of the T killer cell into T killer memory cells and active T killer cells. The clones of the active T killer cells bind to infected cells presenting antigens. T killer cell release chemicals that cause pores to form in the infected cell, causing lysis. The infected cell dies.
257
What are enzymes?
Proteins
258
What is the role of dna loop in a chloroplast?
contains genes for some of their proteins
259
What is genomics
the study of genomes (DNA)
260
what is the overall aim of photosynthesis
to split apart the strong bonds in water molecules, storing the hydrogen in a fuel (glucose) by combining it with carbon dioxide and releasing oxygen into the atmosphere.
261
What are examples of how a physical barrier may cause geographical isolation?
Floods, volcanic activity, eruptions and earthquakes.
262
What is CF?
It is caused by a recessive allele so they must inherit one recessive allele from each parent. If one person is heterozygous they wont have it but they'll be a carrier.
263
How can biodiversity be measured within a species?
Using genetic diversity
264
How did Meselson and Stahl's classic experiment support the theory of semi-conservative DNA replication?
1. Two samples of bacteria were grown- one in a nutrient broth containing light nitrogen and one with heavy nitrogen. As bacteria reproduced they took up nitrogen to make the nucleotides so gradually nitrogen became a part of the DNA.
2. They placed bacteria from the heavy broth in the light nitrogen broth and allowed one round of DNA replication.
3. They then centrifuged it and found that the newly replicated DNA sat in the middle, suggesting its semi-conservative.
265
What are ribosomes and what is their role?
produce proteins from mRNA
266
What is the function of the nucleolus?
The nucleolus makes ribosomes
267
What bonds holds the bases of the polynucleotides together?
Hydrogen bonds
268
What are proteins made up of?
One or more polypeptides.
269
Community
the interaction of different species in the same area
270
What is the same and what is different about STR on different chromosomes
They occur at the same place (same loci) however the number of times they are repeated varies
271
How does evolution occur
Through gene mutation and natural selection
272
What is the smooth ER?
A system of membranes enclosing a fluid filled space but has no ribosomes.
273
Why is it important for the scientific community to critically evaluate new data?
So scientists can share their discoveries in meetings and scientific journals. If scientists generally agree it can lead to an organism being reclassified or lead to changes in the classification system structure.
274
How is energy stored in ATP
ADP + Phosphate ion join together forming ATP in water. To make ATP the phosphate ion must be separated from the water molecule which requires energy.
275
What changes can cause reproductive isolation?
1. **Seasonal changes-** individuals from the same population develop different flowering or mating seasons, or become sexually active at different times of the year.
2. **Mechanical changes-** changes in genitalia prevent successful mating.
3. **Behavioural changes-** A group of individuals develop courtship rituals that aren't attractive to the main population.
276
How does death and decay impact the carbon cycle?
CO2 is released during the breakdown by microbes
277
What is the function of centrioles?
Involved with the separation of chromosomes during cell division.
278
What is an example of artificial active immunity?
when vaccinations stimulate the immune system leading to production of antibodies
279
What is the structure of a strand of DNA and RNA?
polynucleotides composed of mononucleotides linked through condensation reactions.
280
How does respiration impact the carbon cycle?
The oxidation of organic substance into simpler inorganic compounds such as COs and water
281
Explain what happens once the antibodies are produced by the B cell
Antibodies bind to the bacteria with antigens on the surface and label them. Antibodies bind to the antibody receptors on a macrophage. The macrophage engulfs the antibodies and bacterium. Lysosomes fuse with the vacuole releasing the digestive enzymes that destroy the bacterium.
282
What is the description of the nucleus?
A large organelle surrounded by a nuclear envelope which contains many pores. The nucleus contains chromatin (made from DNA and proteins) and the nucleolus.
283
How do you investigate the effects of antibiotics on bacterial growth?
-Sterile pipette to transfer bacteria to agar plate -Use sterile forceps to place paper discs soaked with different antibiotics. -Lightly tape lid, invert and incubate at 25C for 24-48 hrs -The larger the clear zone the more the bacteria were inhibited from growing.
284
when can forensic entomology not be used?
If temperature conditions of the body haven't been fairly constant
285
What are the two nucleotide strands described as being?
Antiparallel as they run in opposite directions
286
Phagocytes
white blood cells that engulf antigens. Inc neutrophils and macrophages.
287
What is a capsule and what is its role?
protects the bacterium from attack by cells of the immune system
288
What is crucial to speciation?
Reproductive isolation (some kind of isolating mechanism) that prevents successful interbreeding and prevents gene flow
289
Give examples of an organisms behavioural adaptations
Possums sometimes play dead, they play dead to escape attack which increases their chance of survival.
Scorpions dance before mating
290
What is the definition for incomplete dominance?
When a trait for a dominant allele isn't completely shown over the trait produced by the recessive allele, so both alleles influence the phenotype.
291
What would happen if the substrate concentration became the limiting factor?
The addition of more enzyme molecules would make no effect on the rate of reaction.
292
What are the complementary base pairs in DNA?
A and T, and C and G
293
What is the induced fit model?
The enzyme substrate complex do have to fit together in the first place but the enzyme substrate complex changed shape slightly to fit. This locks the substrate even more tightly to the enzyme.
294
What are the two Hardy Weinberg equations?
p + q = 1
p2 + 2pq + q2 = 1
295
What are pili and what is their role?
Short hair like structures Pili help bacteria stick together and to other cells
296
How do the rough ER and Golgi apparatus help in the formation of extracellular enzymes?
The extracellular enzymes are modified in the vesicles and then are transported around the cell and then moved to the cell and secreted.
297
What are 4 ways we can recognise that climate change is real?
CO2 levels, temperature records, pollen in peat bogs and dendrochronology
298
What kind of proteins are made at the rough ER? vs in free floating ribosomes in the cytoplasm?
Rough ER- Proteins that are excreted or attached to the cell membrane
Free ribosomes- make proteins that stay in the cytoplasm
299
What is molecular phylogeny and what does it look at?
Looks at molecules (DNA and proteins) to see how closely related organisms are.
300
what is secondary succession?
on bare soil where an existing community has been cleared eg ploughed field or a forest fire
