Biology Paper 1 Flashcards
(76 cards)
1
Q
Explain how the counter-current principle allows efficient oxygen uptake in the fish gas exchange system
A
- Blood and water flow in opposite directions
- Concentration gradient maintained along length of lamella
2
Q
Compare and contrast mitosis and meiosis
A
- Division of body cells
- results in 2 diploid daughter cells
- genetically identical
- used for growth, repair, and cell replacement
Meiosis:
1. germline cells divide into sex cells
2. 4 haploid daughter cells
3. genetic variation due to:
4. crossing over
5. random orientation
6. used for sexual reproduction
Similarities
1. Start as diploid cells
2. Same basic stages prophase, metaphase, anaphase, telophase
3
Q
Qualitative Benedict’s Positive Test colour changes
A
Blue —> green —> yellow —> orange —> brick red
4
Q
Active Transport
A
The movement of substances across a cell membrane through a carrier protein against a concentration gradient, from a low to high concentration with the expenditure of ATP
5
Q
Describe and explain 3 features of starch that make it good storage molecule
A
- Insoluble in water so doesn’t affect water potential
- Branched alpha helix so makes molecule compact
- Branched for large SA for fast hydrolysis
6
Q
Describe and outline 5 functions that proteins hold within an organism
A
- Structural: Keratin
- Enzymes: Pepsin
- Transport: Carrier and integral protein
- Hormones: ADH
- Antibodies
7
Q
(Ultracentrifugation) Explain why the biologist used a blender and then filtered the mixture
A
- Break open cells and produce homogenate
- Remove unbroken cells and larger debris
8
Q
Describe the processes involved in the absorption and transport of digested lipid molecules from the ileum into lymph vessels
A
- Micelles contain bile salts and fatty acids
- Make fatty acids more soluble in water
- Fatty acids absorbed by simple lipid diffusion
- Triglycerides reformed in cells
- Vesicles move to cell membrane
9
Q
Species Richness
A
number of different species in a community
10
Q
Facilitated Diffusion
A
the movement of molecules across a membrane with the assistance of a carrier protein
11
Q
Describe and explain the effect of increasing carbon dioxide concentration on the dissociation of oxyhaemoglobin
A
- More oxygen dissociation
- By decreasing blood pH
12
Q
Diffusion
A
passive movement of particles from a high concentration to a region of low concentration, down a concentration gradient
13
Q
Factors affecting enzyme activity (4)
A
- Temperature
- pH
- Substrate conc
- Enzyme conc
14
Q
Explain why it is more useful to calculate an index of diversity than to record species richness
A
- Index of diversity also measures population size of each species
- So useful because may be many of some species and less of others.
15
Q
Monoclonal Antibodies
A
Antibodies produced from cloned plasma B lymphocytes
16
Q
Non-Reducing Sugars
A
- Add 2cm³ of food sample then add 2cm³ of dilute HCl and heat.
- Add 2cm³ of NaHCO3 then do test for reducing sugars
17
Q
Monomer
A
Smaller units from which larger molecules are made
18
Q
Stages of response to a non-self antigen found in body fluid
A
- Ingestion (phagocytosis).
- Antigen Presentation.
- Clonal Expansion.
- Differentiation (T-cells and cell mediated immunity).
- Differentiation (B-cells and antibody mediated immunity)
19
Q
Order of Organelles
A
Nuclei, Chloroplasts, Mitochondria, Lysosomes, Endoplasmic Reticulum, Ribosomes
20
Q
What is the proteome of a cell?
A
The full range of different proteins that a cell is able to produce at a given time
21
Q
Describe the role of one named organelle in digesting bacteria
A
- Lysosomes
- Fuse with vesicle
- Releases hydrolytic enzymes (lyzozymes)
22
Q
Describe the fluid mosaic Structure
A
Fluid: All the components can move around.
Mosaic: Many different components all fit together
23
Q
Explain how the chromosome number is halved during meiosis
A
- Homologous chromosomes pair
- One of each pair goes to each to opposite poles
24
Q
Apart from mutation, explain one other way genetic variation within a species is increased
A
- Random fusion of gametes
- Produces new allele combinations
24
Co-Transport
1. The simultaneous transport of two different substances through one carrier protein.
2. One substance (usually an ion) moves down its concentration (passive) whilst the other substance is transported against its concentration gradient (active transport)
25
Antibody
A protein molecule that can bind specifically to an antigen
26
Test for Lipids
1. Mix Test solution with ethanol.
2. Shake for 1 minute then add water.
3. Cloudy white emulsion
27
Pulmonary Ventilation
Tidal volume x Ventilation rate
28
Cardiac Output
stroke volume x heart rate
29
Describe the roles of micelles in the absorption of fats into the cells lining the ileum
1. Micelles include bile salts and fatty acids.
2. Makes fatty acids more soluble in water
3. Brings fatty acids towards the lining
4. Fatty acids absorbed by diffusion
30
Determining the genome of the viruses could allow scientists to develop a vaccine. Explain how
1. The scientists could identify proteins that derive from the genetic code
2. They could then identify potential antigens to use in the vaccine
31
Prophase
1. DNA winds up making chromosones from chromatin.
2. Centrioles appear at opposite poles of the cell.
3. Nucleolus disappears
32
Interphase G2
Spindle fibres are made
33
Describe how a phosphodiester bond is formed between two nucleotides within a DNA molecule
1. Condensation reaction
2. Between phosphate and deoxyribose
3. Catalysed by DNA polymerase
34
Addition
Nucleotide is gained from a DNA strand, creating a right frameshift
35
Population
a group of individuals that occupy the same habitat at the same time and are potentially able to interbreed
36
what is passive immunity and how is it produced?
produced by the introduction of antibodies into individuals from an outside source.
immunity is acquired immediately but not lasting e.g. anti-venom
37
why don't triglycerides affect water potential?
large and insoluble
38
how does courtship behaviour result in reproductive success?
1. allowing recognition of own species
2. identifying those capable of breeding
3. forming a pair bond
4. synchronising mating
39
Instraspecific Competition
occurs when individuals of the SAME species compete for resources such as foo, light, water etc.
40
What enzyme unwinds DNA during replication?
Helicase
41
advantages of an electron microscope?
electron beam has a short wavelength and the microscope can therefore has high resolution.
the negatively charged beam can be focused using electromagnets
42
where is amylase produced?
salivary glands, pancreas, small intestine
43
how can you make an experiment more valid?
controlling more variables and/or using a control
44
Why is cell fractionation carried out at low temperatures?
reduce enzyme activity that may break down the organelles
45
stabilising selection
if environmental conditions are the same, those with alleles closer to the mean are favored. they are more likely to survive and reproduce e.g. birth weight.
46
glucose+galactose=
lactose
47
ecosystem
made up of a community and all the non-living factors of its environment. It includes all the living organisms that interact with one another and also with the physical and non-physical factors present
48
glycogen
Carbohydrate store in animals
49
what type of bond forms between the phosphate group and deoxyribose sugar in DNA?
phosphodiester bond
50
structose of amylose
straight coils
50
artificial active immunity
involves inducing an immune response in an individual
WITHOUT them suffering the symptoms of the disease.
e.g. vaccinations
memory cells produced
51
what is haemoglobin made up of?
two α polypeptide chains
two β polypeptide chains
an inorganic prosthetic haem group (Fe2+)
52
gas exchange system in an insect
Spiracles > trachea > tracheoles > diffusion of gases into cells
53
Describe how carbon dioxide in the air outside a leaf reaches mesophyll cells inside the leaf (3)
it enters via stomata, which are opened as guard cells open. if diffuses down a concentration gradient through the air spaces
54
two forms of starch
amylose and amylopectin
55
secondary sequence of a protein
The way in which the primary structure of a polypeptide chain folds e.g. alpha helix or beta pleated sheets. shape is held by H bonds
56
primary sequence of a protein
The unique sequence of amino acids that make up a protein or polypeptide chain
56
where is maltase produced?
epithelium of small intestine
57
how does a scanning electron microscope work?
it directs an electron beam onto a specimen surface rather than penetrating it.
the beam is passed back and forth across a specimen in a regular pattern, depending on its contours
a computer is used to build up a 3D image
57
role of a T helper cell?
Receptors attach to antigens on antigen presenting cell. This attachment activates T cells to divide rapidly by mitosis and form a clone of genetically identical cells
58
directional selection
selection favours individuals in one direction from the mean of the population.
e.g. when environment changes, those with advantageous allele outside of the mean will be more likely to survive and breed
59
what happens during independent segregation?
during meiosis 1
each chromosome aligns with its homologous partner at the equator of the cell
the combination of maternal/paternal chromosomes aligns randomly
one chromosome of each pair goes to daughter cell- by chance
60
limitations of using a transmission electron microscope?
the whole system must be in vacuum, so living specimens cant be studied.
complex staining process
the image may contain artefacts
61
process of expiration
internal intercostals contract, external intercostals relax. ribs movie in and downwards. diaphragm relaxes.
this decreases thorax volume
air pressure in lungs becomes greater than atmospheric pressure, so air is forced out
62
osmosis
the movement of water molecules across a semi-permeable membrane from an area of higher water concentration to an area of lower water concentration
63
active transport
the movement of molecules across a biological membrane from an area of lower concentration to an area of higher concentration, against the concentration gradient
64
co-transport
coupled movement of substances across a cell membrane via a carrier protein
65
what is meant by the term resolution
the ability to see two objects that are close together
66
explain why the ileum contains both endopeptidases and exopeptidases for efficient digestion of proteins
endopeptidases hydrolyse internal peptide bonds
endopeptidases create more ends for exopeptidases
67
describe and explain how an artery is adapted to its function
thick muscle wall to withstand high blood pressure
narrow lumen to maintain high blood pressure
elastic tissue to stretch and recoil to maintain blood pressure
68
function of the coronary arteries
carry oxygen to the heart muscles
69
describe how glycoproteins would be produced in the cell
amino acid chain/protein leaves ribosome in the cytoplasm
travels in golgi in vesicle to be modified
carbohydrate chain added to protein at golgi
70
adaptations of cacti to the desert habitat
hair around the stomata- trap water vapour/moisture and reduce water potential gradient
stomata in pits/sunken pits- trap water vapour and reduce diffusion gradient
fewer stomata- reduces diffusion
thick cuticle- which is impermeable
71
compare the structure of triglycerides and phospholipids
both contain fatty acid chains
both contain ester bonds
both contain glycerol molecules
triglycerides contain 3 fatty acid chains and phospholipids contain two
phospholipids contain a phosphate group bound to the glycerol and triglycerides do not
72
explain the steps in meiosis that lead to an increase in genetic variation
homologus chromosomes pair up
independent segregation in metaphase 1
maternal and paternal chromosomes are re-shuffled in any combination which gametes receive maternal/ paternal chromosome
crossing over leads to exchange of parts on non-sister chromatids between homologus chromosomes in prophase 1
both create new combinations of alleles
