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AP® Biology flashcards Biology 101 flashcards
1
Q 
7. Which sequence of DNA would be suitable in DNA profiling?  (May 2016)
A. ---ATTCGTGAATCAGCC---
B. ---ATTCGTGAATTTGCC---
C. ---ATTCGTGATTGCAGC---
D. ---ATTCGTGATTCGTGA---
A

D

DNA profiling requires short tandem repeats. D has repeating unit ATTCGT

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2
Q
  1. What is the mechanism of sodium-potassium pumps in neurons that generates a resting potential by active transport? (May 2016)
    A. K+ from cytoplasm binds to the pump and stimulates its phosphorylation by ATP.
    B. Phosphorylation of the pump causes its shape change in order to move Na+ into the cytoplasm.
    C. K+ from inside the cell binds to the pump and causes the release of the phosphate group.
    D. Na+ from cytoplasm binds to the pump and stimulates its phosphorylation by ATP.
A

D.

Na+ from cytoplasm inside neurons enter pump
ATP –> ADP + Pi, Pi attach to pump
Pump change shape to release Na+ outside of neuron
Entry of K+ ions release the phosphate group

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3
Q
  1. What is the effect of dominant alleles? (May 2016)
    I. They mask the effect of recessive alleles.
    II. They become more frequent than recessive alleles in a population.
    III. They have a joint effect with recessive alleles when characteristics are co-dominant.
    A. I only
    B. I and II only
    C. I and III only
    D. I, II and III
A

A
Only co-dominant alleles have joint effects.
Dominant alleles mask the effect of recessive alleles

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4
Q
  1. What event occurs only in meiosis? (May 2016)
    A. Fusion of gametes to promote genetic variation
    B. Random separation of chromatids
    C. Random separation of homologous chromosomes
    D. Replication of chromosomes
A

C

92 chromosomes to 46 chromosomes in anaphase 1

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5
Q

“Bacteria play an important role in recycling nutrients in ecosystems. They live on organic wastes and dead organisms and digest their molecules. They then absorb some of these molecules for their own metabolism, and the rest is used by other
organisms.”

24. What is the mode of nutrition of these bacteria? (may 2016)
A. They are autotrophs.
B. They are consumers.
C. They are saprotrophs.
D. They are detritivores.
A

C
Detritivores obtain organic nutrients by internal digestion
Saprotrophs: external digestion
Both are heterotrophs

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6
Q
  1. How can molluscs and platyhelminthes be distinguished? (may 2016)
    A. Molluscs are unsegmented but platyhelminthes are segmented.
    B. Molluscs have a mouth and an anus but platyhelminthes do not.
    C. Molluscs are smooth but platyhelminthes have bristles.
    D. Molluscs remain attached to rock but platyhelminthes move around in water.
A

B
Platyhelminthes have no segmentation; molluscs have non-visible segmentation

Molluscs have shells made of CaCO3; bristles present in annelida, platyhelminthes have stinging cells and tentacles

porifera attach to rocks

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7
Q
  1. Which is the most efficient way for some desert plants to conserve water? (may 2016)
    A. By having no leaves, so water evaporates from the green stem with less surface
    B. By loading organic compounds in the phloem of the roots
    C. By accumulating salt within their tissues, so water is retained by osmosis
    D. By growing long hair on their surface, so air moisture is absorbed at night
A

A
Reduced leaves reduce surface area available for water loss
stomata in pits surrounded by hair traps water vapour and reduce transpiration

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8
Q
  1. How can species of bacteria evolve to be resistant to antibiotics? (may 2016)
    I. A variation within one bacterium’s genome confers resistance.
    II. Antibiotics enable genes to become adapted through transcription and translation.
    III. An incomplete dose of antibiotics allows bacteria with a high resistance to survive and reproduce.

A. I only
B. I and II only
C. I and III only
D. III only

A

C

Through mutation, selection, horizontal transfer

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9
Q
  1. What happens to starch in the small intestine? (may 2016)
    A. Endopeptidase secreted by the liver digests starch to enable absorption by the villi.
    B. Contraction of intestinal muscle mixes starch with enzymes to accelerate its conversion into
    amylose.
    C. Glycogen secreted by the pancreas hydrolyses starch into glucose, which is eventually
    transported to the liver.
    D. Amylase secreted by the pancreas digests starch to enable absorption by the villi.
A

D

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10
Q
  1. Testosterone is a hormone that is important for male reproductive development.
    The molecule contains the following:CH3, OH, double bond O, CH3
    To which group of compounds does testosterone belong? (Nov 2021)
    A. Nucleotides
    B. Carbohydrates
    C. Lipids
    D. Amino acids
A

C

YOU JUST HAVE TO LEARN IT OFF BY HEART

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11
Q
  1. The image shows the structure of the protein hemoglobin.
    What level of protein structure bonds the α and β chains together? (Nov 2021)
    A. Primary
    B. Secondary
    C. Tertiary
    D. Quaternary
A

D
hemoglobin is made of four chains of polypeptide. The quaternary structure exists in proteins with more than one polypeptide chain.

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12
Q 
11. Down syndrome can be detected before birth by chorionic villus sampling. From where are the cells for this test taken? (Nov 2021)
A. Amniotic fluid surrounding the fetus
B. Fetal digestive system
C. Tissue in the placenta
D. Lining of the uterus of the mother
A

C
Topic 3.3 application
Amniocentesis involves passing a needle thru mother’s abdomen wall, using ultrasound to guide. Needle withdraw a sample of amniotic fluid containing fetal cells from the amniotic sac
Chorionic villus sampling enters the vagina to obtain cells from the chorion, one of the membranes from which the placenta develops.

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13
Q
  1. How do greenhouse gases contribute to global warming? (Nov 2021)
    A. They destroy the ozone layer, allowing radiation to reach the Earth’s surface.
    B. They prevent radiation from the Earth escaping into space.
    C. They trap short wavelength radiation in the atmosphere.
    D. They are a product of combustion, which generates heat.
A

B
Sun emits short wavelength, greenhouse gases trap long wavelength
Ozone depletion is caused by free radical catalyst turning O3 to O2

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14
Q
  1. What occurs as a result of a cut in the skin of a finger? (Nov 2021)
    A. Prothrombin is transformed into thrombin.
    B. Fibrin is converted to insoluble fibrinogen.
    C. Platelets produce antibodies to prevent infection.
    D. Clotting factors are released from red blood cells.
A

A

Fibrinogen (soluble) is converted to Fibrin

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15
Q
  1. The graph shows changes in the membrane potential in an action potential.
    What is the approximate value of the threshold potential? (Nov 2021)
    A. −88mV
    B. −70mV
    C. −50mV
    D. +45mV
A

C
Threshold potential is -50mV (the potential that causes a big increase)
Resting potential is -70mV

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16
Q
  1. A dihybrid cross was carried out between two plants to determine whether the genes for seed shape and colour are linked. If the genes are unlinked, the expected ratio of 9:3:3:1 should occur. A chi-squared test was carried out on the observed results of the cross. The critical value for chi-squared at the 5% level of significance in this test was 7.82. The calculated value for chi squared was 6.25. What can be concluded from this data? (Nov 2021)
    A. The results prove that the genes are linked.
    B. The results prove that the genes are unlinked.
    C. There is significant evidence that the genes are linked.
    D. There is significant evidence that the genes are unlinked.
A

D
Chi squared lower than critical value of chi-squared so do not reject null
Null is always that the genes are unlinked

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17
Q
  1. What is the primary function of the free ribosomes shown in the electron micrograph? (Nov 2021)

A. Synthesize proteins to be used within the cell
B. Synthesize proteins for use in lysosomes
C. Carry amino acids to mRNA for protein synthesis
D. Synthesize proteins for secretion

A

A
Free ribosomes synthesise proteins for use primarily within the cell
Bound ribosomes synthesise proteins primarily for secretion or for use in lysosomes

18
Q
  1. Which properties explain the ability of water to dissolve solutes? (Nov 2016)
    I. Polarity of water molecules
    II. High specific heat capacity of water
    III. Hydrogen bonding
A

1+3
Textbook P.70 Water forms hydrogen bonds with polar molecules. Its partially negative oxygen pole is attracted to positively charged ions and its partially positive hydrogen pole is attracted to negatively charged ions
The high specific heat of water makes it resistant to temperature change, allowing life forms to maintain relatively constant internal temperatures.

19
Q 
17. Which evidence for evolution do the common features in the bone structure of vertebrate limbs
provide? (Nov 2016) (topic 5.1)
A. Adaptive radiation
B. Divergent radiation
C. Convergent evolution
D. Discontinuous variation
A

A
adaptive: organisms from same ancestor have different selective pressures in the environment, so they adapt their structures to perform different functions

Divergent radiation: NO SUCH THING

Convergent: organisms from different ancestors have the same selective pressure in the environment, so their structures converge to perform similar functions

Discontinuous variation: topic 10.2, characteristics affected by one gene, express one phenotype

20
Q 
20. What is the main method of transport of monosaccharides such as fructose across the
intestinal epithelium? (Nov 2016)
A. Osmosis
B. Facilitated diffusion
C. Endocytosis
D. Active transport
A

B
Fructose by facilitated diffusion (fructose is five ring while glucose is six ring)
Glucose is polar so hydrophilic, co-transport with sodium ions (actively transported)

21
Q
  1. Where does a tRNA-activating enzyme attach the appropriate amino acid to the tRNA molecule? (Nov 2016)
A

The side with no circle
Attachment of an amino acid to the f3-terminal of the tRNA by tRNA-activating enzyme
The active site of the activating enzyme is specific to both the correct amino acid and the correct tRNA

22
Q
  1. What is/are the effect(s) of auxin in plants? (Nov 2016)
    I. Increasing the rate of cell elongation in stems
    II. Changing the pattern of gene expression in shoot cells
    III. Detecting the direction of light
A

1+2

Phototropins (PIN3 proteins) detect light and transport auxin

23
Q
  1. Excessive irrigation can cause increased salinity in the soil. What effect does this have on water transport in the plant roots? (Nov 2016)
    A. Decreases movement of water from soil into the root
    B. Absorption of water with a higher solute concentration
    C. Increases movement of water from soil into the root
    D. Absorption of water with a lower solute concentration
A

A
Textbook P.408 the concentrations of mineral ions in the root can be 100 or more times higher than those in the soil
Higher solute concentration in soil would lower the concentration gradient of solute established by active transport
So less osmosis with lower solute concentration gradient (difference in solute conc. between roots and soil)

24
Q
  1. Chrysanthemums are an important commercial flower. As a short-day plant, how can growers induce chrysanthemums to flower out of season? (Nov 2016)
    A. Expose plants to short bursts of light for 24 hours
    B. Expose plants to 15 hours of continuous light
    C. Expose plants to 12 hours of light and 12 hours of darkness
    D. Expose plants to 15 hours of continuous darkness
A

D

Short-day plant require minimum darkness to flower

25
Q 
38. What is required for a skeletal muscle to exert force? (Nov 2016)
A. Extensor and flexor muscles
B. Synovial joints
C. Attachment to bones
D. Ligaments
A

C
Bones and exoskeletons provide anchorage for muscles and act as levers (levers change size and direction of forces)
Extensor: triceps extend the joint
Flexor: biceps flex the joint
Synovial joints only allow certain movements
Ligaments: hold bones together
Tendons: connect muscles to bones

26
Q
  1. The diagram shows part of a molecule. (May 2021 TZ2)
    alpha glucose, 1-4 glycosidic bonds, looks linear
    What is the molecule?
    A. Amylose
    B. Cellulose
    C. Collagen
    D. Amylopectin
A

D
amylose and amylopectin are two types of starch. Amylose is unbranched, has a coiled structure. amylopectin is branched.
cellulose consists of unbranched beta-glucose
1-6 glycosidic bonds create branching points

27
Q 
10. What is a feature of the human genome? (May 2021 TZ2)
A. Plasmids
B. Messenger RNA
C. Transfer RNA
D. Mitochondrial DNA
A

D
Prokaryotes do not contain mitochondria
It has 70s ribosomes and carries out protein synthesis so has mRNA and tRNA

28
Q
  1. What information can be deduced from the sequence of nodes in a cladogram? (May 2021 TZ2)
    A. The geological period in which the species in the clade diverged from their common ancestor
    B. The probable sequence of divergence among the species in the clade
    C. The number of characteristics the species have in common
    D. The number of mutations that have occurred since the species shared a common ancestor
A

B

The node represents a hypothetical ancestral species that split to form two or more species

29
Q
  1. The diagram shows changes in pressure in the left atrium, left ventricle and aorta during a single
    cardiac cycle. At what point during the cycle does the atrioventricular valve close? (May 2021 TZ2)
A

Before the rise in pressure of the left ventricle.

Ventricle contraction during high pressure closes AV valves to prevent backflow of blood

30
Q
  1. What is a similarity between the testes of males and the ovaries of females in humans? (May 2021 TZ2)
    A. They produce gametes throughout the life of the individual.
    B. They secrete hormones into the blood stream.
    C. Their development is controlled by a gene on the Y chromosome.
    D. They release products to the outside of the body directly through the urethra.
A

B

Oogenesis stops at menopause while spermatogenesis continuous until death

31
Q 
18. A fluid sample is taken from the digestive tract of a mammal. The sample is basic (alkaline) and able to digest starch and proteins. From which part of the digestive tract was the fluid taken? (May 2021 TZ1)
A. Mouth
B. Stomach
C. Small intestine
D. Gall bladder
A

C
Mouth unable to digest protein
stomach fluid is acidic
gall bladder doesn’t contain any digestive enzymes

32
Q
  1. What are the evolutionary origins and functions of homologous structures? (May 2021 TZ1)
    A. common or different origin; same function
    B. common origin; same or different function
    C. different origin; same function
    D. different origin; same or different function
A

B
Homologous: common ancestor, similar structures, different functions
analogous: different ancestors, same functions

33
Q 
11. Which genotype would be normally found in a gamete? (May 2021 TZ1)
A. Rr
B. RS
C. rStt
D. TUt
A

B
Gamete is haploid (single set of unpaired chromosomes/one copy of gene)
Rr implies diploid
rStt - gamete undergone disjunction?

34
Q
  1. The Davson–Danielli model of membrane structure proposed that membranes were composed of a
    phospholipid bilayer that lies between two layers of globular proteins. What evidence supported this model?
    A. An electron micrograph that showed two dark lines with a lighter band in between
    B. Freeze-fracture electron microscopy
    C. Evidence that all membranes are identical
    D. The hydrophobic regions of protein would be in contact with water
A

A

35
Q
  1. Which statement applies to tRNA? (May 2021 TZ1)
    A. There is at least one type of tRNA that combines with each known amino acid.
    B. One type of tRNA can combine with all of the known amino acids.
    C. tRNA carries out its main role within the nucleus.
    D. tRNA is produced by the process of translation.
A

A

tRNA is shape specific. different tRNA is needed for different amino acids

36
Q 
38. What is normally found in the urine of a healthy individual? (May 2021 TZ1)
A. Glucose
B. Red blood cells
C. Proteins
D. Sodium ions
A

D

protein is too big to enter the glomerulus

37
Q
  1. The pregnancy test for humans is based on detection of the hormone HCG. What is the reason for
    detection of this hormone indicating pregnancy?
    A. HCG is involved in milk production.
    B. HCG production is blocked by negative feedback during menstruation.
    C. HCG is produced by an embryo.
    D. HCG is released during the acrosome reaction.
A

C

38
Q 
15. Which organisms produce methane in anaerobic environments such as waterlogged soils? (May 2019 TZ1)
A. Archaea
B. Fungi
C. Eukaryotes
D. Eubacteria
A

A

39
Q
  1. What would show that a person has developed metastatic cancer?
    A. Alveolus cells forming a tumour in the lungs
    B. Cancer cells producing the skin pigment melanin in the liver
    C. A tumour in the prostate gland increasing levels of prostate-specific antigen
    D. Cancerous lymphocytes in blood plasma
A

B

40
Q
  1. Chlorella and Paramecium are both unicellular eukaryotic organisms living in freshwater.
    Chlorella is photosynthetic and has a cell wall. Which organelle will be found in Paramecium
    but not in Chlorella?
    A. Chloroplast
    B. Contractile vacuole
    C. Rough endoplasmic reticulum
    D. Mitochondrion
A

B

41
Q
  1. The oceans absorb much of the carbon dioxide in the atmosphere. The combustion of fossil
    fuels has increased carbon dioxide ocean concentrations. What adverse effect does this
    have on marine life?
    A. Heterotrophs consume more phytoplankton.
    B. Phytoplankton have increased rates of photosynthesis.
    C. Corals deposit less calcium carbonate to form skeletons.
    D. Increased pH reduces enzyme activity in marine organisms.
A

B

Biology (13 decks)

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