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2024 AQA AS LEVEL BIOLOGY RANDOM EXAM QUESTIONS WITH ANSWERS
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2024 AQA AS LEVEL BIOLOGY RANDOM EXAM QUESTIONS WITH ANSWERS
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2024 AQA AS LEVEL BIOLOGYRANDOM EXAM QUESTIONS WITH
ANSWERS
What are the differences between hypotonic and hypertonic solutions? -
CORRECT-ANSWERSHypotonic= higher water potential outside cell
Hypertonic=lower water potential outside cell
How does an animal cell respond to hypotonic and hypertonic solutions? -
CORRECT-ANSWERSHypotonic= water moves in via osmosis and cell bursts
(lysis)
Hypertonic= water moves out via osmosis and cell shrinks and crenates
What are genetic bottlenecks? - CORRECT-ANSWERS1. causes huge
reduction in population
2. so reduces number of different alleles in gene pool
3. so genetic diversity decreased
4. survivors reproduce and a larger population is created from a few
individuals
One mutation causing phenylketonuria was originally only found in one
population in
central Asia. It is now found in many different populations across Asia.
Suggest how
the spread of this mutation may have occurred. - CORRECT-
ANSWERSFounder effect / colonies split off /
migration / interbreeding
Scientists can use protein structure to investigate the evolutionary
relationships
between different species. Explain why - CORRECT-ANSWERS1. Amino acid
sequences / primary
structure
2. Closer the (amino acid) sequence
the closer the relationship
3. (Protein structure) related to
(DNA) base/triplet sequence
, Comparing the base sequence of genes provides more evolutionary
information than
comparing the structure of proteins. Explain why - CORRECT-ANSWERS1.
Reference to base triplets/triplet
code / more bases than amino
acids / longer base sequence
than amino acid sequence
2. Introns / non-coding DNA
3. Degeneracy of code / more than
one code for each amino acid
Root pressure moves water through the xylem. Describe what causes root
pressure. - CORRECT-ANSWERS1. Active transport by endodermis
2. ions/salts into xylem
3. Lowers water potential (in xylem)
4. (Water enters) by osmosis
Explain what is meant by a genetic bottleneck. - CORRECT-ANSWERS1. Drop
in population / many killed / only
single female left
2. Idea of reduced/low genetic
variation/diversity / reduction in
(variety of) alleles / smaller gene pool
Explain how oxygen is loaded, transported and unloaded in the blood. -
CORRECT-ANSWERS1. Haemoglobin carries oxygen /
has a high affinity for oxygen /
oxyhaemoglobin
2. In red blood cells
3. Loading/uptake/association in
lungs
4. at high p.O2
5. Unloads/ dissociates / releases to
respiring cells/tissues
6. at low p.O2
7. Unloading linked to higher carbon
dioxide (concentration)
Describe the process of translation. - CORRECT-ANSWERS1. tRNA collects
specific amino acid from cytoplasm and brings it to a ribosome, attached to
mRNA by small subunit
2. tRNA attaches to mRNA codon by complementary anticodon. 2 tRNA
molecules can attach at once as 6 bases/2 codons of mRNA are exposed
3. amino acids attached to 2 tRNA molecules are held closely together and
peptide bonds form between them
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