AQA AS BIOLOGY 7401/1 Paper 1/ Practice Test
The human cell then makes a complementary strand to the HIV DNA.
The complementary strand is made in the same way as a new complementary
strand is made during semi-conservative replication of human DNA. Describe how the complementary strand of HIV D...
AQA AS BIOLOGY 7401/1 Paper 1/ Practice Test
The human cell then makes a complementary strand to the HIV DNA.
The complementary strand is made in the same way as a new complementary
strand is made during semi-conservative replication of human DNA. Describe how
the complementary strand of HIV DNA is made. - CORRECT ANSWER-- there are
complementary nucleotides/bases pair
- DNA polymerase used
- Nucleotides join together (to form new strand)/phosphodiester bonds form;
Contrast the structures of DNA and mRNA molecules to give three differences. -
CORRECT ANSWER-- DNA is double stranded/double helix and mRNA single-
stranded;
- DNA (very) long and RNA short;
-Thymine/T in DNA and uracil/U in RNA;
- Deoxyribose in DNA and ribose in RNA;
Describe the difference between the structure of a triglyceride molecule and the -
CORRECT ANSWER-In phospholipid, one fatty acid replaced by a phosphate
Describe how you would test for the presence of a lipid in a sample of food -
CORRECT ANSWER-- Add ethanol, then add water;
-White (emulsion shows lipid)
Describe how a saturated fatty acid is different from an unsaturated fatty acid -
CORRECT ANSWER-Unsaturated has (at least one) double bond (between
carbons)
This fat substitute cannot be digested in the gut by lipase. Suggest why. - CORRECT
ANSWER-- (Fat substitute) is a different/wrong shape/not complementary
- Unable to fit/bind to (active site of) lipase/no ES complex formed;
Despite being a lipid, the substitute cannot cross the cell-surface membranes of cells
lining the gut.
Suggest why it cannot cross cell-surface membranes. - CORRECT ANSWER-It is
hydrophilic/is polar/is too large/is too big;
Cells constantly hydrolyse ATP to provide energy. Describe how ATP is
resynthesised in cells. - CORRECT ANSWER-- From ADP and phosphate;
- By ATP synthase;
- During respiration/photosynthesis;
Give two ways in which the hydrolysis of ATP is used in cells. - CORRECT
ANSWER-- To provide energy for other reactions/named process;
- To add phosphate to other substances and make them more reactive/change their
shape
What is the evidence from Figure 2 that a scanning electron microscope was used to
take this photograph? - CORRECT ANSWER-(Can see) 3D image
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