Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Biology > Exam Questions > Flashcards

Exam Questions Flashcards

You may prefer our related Brainscape-certified flashcards:
AP® Biology flashcards Biology 101 flashcards
1
Q

What is a homologus pair of chromosomes? (1)

A

Two chromosomes that carry the same genes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is meant by species richness? (1)

A

A measure of the number of different species in a community

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Formation of an enzyme substrate complex increases the rate of reaction. Explain how. (2)

A

Reduces activation energy

Due to bending of bonds

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Heat stress decreases the light-dependent reaction of photosynthesis. Explain why this leads to a decrease in the light-dependent reaction. (2)

A

Less/no ATP

Less/no reduced NADP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

A decrease in the activity of the enzyme rubisco would limit the rate of photosynthesis. Explain why. (2)

A

Less/no CO2 reacts with RuBP

Less/no GP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Describe how alterations to tumour suppressor genes can lead to the development of tumours (3)

A

Increased methylation of tumour suppressor genes
Mutation in tumour suppressor genes
Tumour suppressor genes are not transcribed/expressed
Results in rapid/uncontrollable cell division

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Describe how you would determine the mean percentage cover for beach grass on a sand dune (3)

A

Method of randomly determining position of quadrats
Large sample of quadrats
Divide total percentage by number of quadrats/samples/readings

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

In genetic crosses, the observed phenotypic ratio obtained is often not the same as the expected ratios. Give two reasons why. (2)

A

Small sample size
Fusion/fertilisation of gametes is random
Linked Genes
Epistasis

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Dopamine is similar to acetylcholine and stimulates the production of nerve impulses in postsynaptic neurones. Describe how. (3)

A

Dopamine diffuses across synapse
Attaches to receptors on postsynaptic membrane
Stimulates entry of sodium ions and depolarisation/action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

GABA is a neurotransmitter, and causes negatively charged Cl- to enter postsynaptic neurones. Explain how this inhibits postsynaptic neurones. (3)

A

Inside of postsynaptic neurone becomes more negative/hyperpolarisation
More sodium ions required to reach threshold
For depolarisation/action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Explain why the antibody binds to the transcription factor. (2)

A

Transcription factor has specific tertiary structure

Complementary shape

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Describe the roles of two enzymes used to insert DNA fragments into plasmids (2)

A

Restriction endonuclease to cut plasmid/vector

Ligase joins DNA to plasmid/vector

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

People with achromatopsia have only rods and no functioning cone cells, and have difficulty seeing in detail. Explain why. (3)

A

No functional cones/only rods
Cones are connected to a single neurone, multiple rods connected to single neurone
Cones send separate impulses to the brain, rods send a single set

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Red-green colour blindness affects more women than men. Explain why. (2)

A

Gene/allele is on X chromosome

Females require two alleles, and males only require one

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

People with red-green colour blindness are unable to distinguish between red and green, but also other colours. Explain why. (3)

A

Green sensitive pigment/ cones non-functional
Three different types of pigment/cone
Other/different colours seen due to stimulation of more than one cone/pigment

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe how oxygen in the air reaches capillaries surrounding alveoli in the lungs. (4 marks)

A 
Trachea and bronchi and bronchioles
Down pressure gradient
Down diffusion gradient
Across alveolar epithelium
Across capillary epithelium
17
Q

Species richness and an index of diversity can be used to measure biodiversity. What is the difference between these two? (1)

A

Species richness measures only number of different species, does not measure number of individuals

18
Q

Explain the difference in the structure of the starch molecule and the cellulose molecule. (2)

A

Starch formed from a-glucose but cellulose from b-glucose

Position on hydrogen and hydroxyl groups on carbon atom 1 inverted

19
Q

Explain one way in which starch molecules are adapted for their function in plant cells (2)

A

Insoluble - doesn’t affect water potential
Helical - compact
Large molecule - cannot leave

20
Q

Explain how cellulose molecules are adapted for their function in plant cells (3)

A

Long and straight chains
Become linked together by many hydrogen bonds to form fibrils
Provide strength to cell wall

21
Q

Contrast the processes of facilitated diffusion and active transport (3)

A

FD involves channel or carrier proteins whereas AT only involves carrier proteins
FD does not use ATP, AT does
FD takes place down a concentration gradient whereas AT can occur against a concentration gradient

22
Q

What is meant by genetic diversity? (1)

A

Number of different alleles of each gene

23
Q

Explain why new nucleotides can only be added in a 5’ to 3’ direction (4)

A

Reference to DNA polymerase
Which is specific
Only complementary to 5’ end of strand
Only complementary with phosphate end of the developing strand

24
Q

Describe the mass flow hypothesis of translocation in plants (4)

A

In source, sugars actively transported into phloem
By companion cells
Lowers water potential of sieve tube and water enters by osmosis
Increase in pressure causes mass movement towards sink
Sugars used in root for respiration for storage

25
Q

mRNA is used during translation to form polypeptides. Describe how mRNA is produced in the nucleus of a cell (6)

A

Helicase
Breaks hydrogen bonds
Only one DNA strand acts as template
RNA nucleotides attracted to exposed bases
According to base pairing rule
RNA polymerase joins RNA nucleotides together
Pre-mRNA spliced

26
Q

Describe the structure of proteins (5)

A

Polymer of amino acids
Joined by peptide bonds
Formed by condensation
Primary structure is order of amino acids
Secondary structure is folding of chain due to hydrogen bonding
Tertiary structure is 3D folding due to H+, Ionic, Disulfide
Quaternary structure is two or more polypeptide chains

27
Q

Describe how proteins are digested in the human gut (4)

A

Hydrolysis of peptide bonds
Endopeptidases break polypeptides into smaller peptide chains
Exopeptidases remove terminal amino acids
Dipeptidases hydrolyse dipeptides into amino acids

28
Q

Key points of chromatography

A

Origin line must be above solvent

Stop chromatography before solvent reaches the end of the paper

Biology (23 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions