Bone marrow contains stem cells. Which statement best describes one of these stem cells?
Question 2
A mutation occurs in a gene that controls cell division in one cell lining a person's lung. The cell begins to divide again and again, even when no new cells are needed. What is the most likely result?
Question 3
Dividing cells along an onion root
Distance from tip (millimeters)
Cells counted
Cells dividing
1
200
41
5
200
12
10
200
2
A student cut thin slices from three places along a growing onion root and counted cells in the middle of dividing (table). Which conclusion is best supported by the data?
Question 4
Researchers removed the nucleus from a frog egg cell and put in its place the nucleus of a fully specialized cell from a tadpole's intestine. Some of these eggs developed into tadpoles with muscle, nerve, skin and gut cells. Which conclusion is best supported by this result?
Question 5
Cells in two dishes
Day
Normal cells
Tumor cells
0
5000
5000
1
10000
10000
2
20000
20000
3
40000
40000
4
40000
80000
5
40000
160000
6
40000
320000
A lab grew normal cells and tumor cells from the same tissue in two dishes with plenty of nutrients, starting each dish with 5000 cells, and counted the cells each day (table). Which statement correctly explains the counts on day 6?
Question 6
Which statement best describes a gene?
Question 7
Large parts of a chromosome are non-coding regions: their DNA is not used as a code for the amino acids of any protein. Which statement best explains why a single base change in a non-coding region often has no effect on the organism's traits?
Question 8
A body cell of a fruit fly has 8 chromosomes, arranged as 4 pairs. Where do the two chromosomes of each pair come from?
Question 9
In pea plants, the gene for flower color sits at the same position on both chromosomes of one pair. One plant has the allele for purple flowers on one of these chromosomes and the allele for white flowers on the other. Which statement about this plant is correct?
Question 10
The pigment gene in five plants
Plant
Change from the typical gene
Region of the change
Enzyme made
Flower color
1
none
none
works
purple
2
one base
coding
one amino acid different, does not work
white
3
one base
non-coding
unchanged, works
purple
4
one base
coding
unchanged amino acids, works
purple
5
three bases missing
coding
one amino acid missing, does not work
white
Flower color in a plant depends on an enzyme that makes purple pigment. A lab compared the enzyme's gene in plants 2 to 5 with the gene in plant 1, a typical purple plant (table). Which claim is best supported by the data?
Question 11
A farmer in the Hudson Valley finds a few tomato plants with yellow fruit among plants of a variety that usually has red fruit. Which question could be investigated in a lab to learn about the role of DNA in this trait?
Question 12
Two brothers have the same mother and father but look quite different. Which statement best explains this?
Question 13
A lifeguard at a beach on Long Island gets bad sunburns for several summers. Ultraviolet light causes a mutation in one of her skin cells. Will her future children inherit this mutation?
Question 14
Scientists insert the human gene for insulin into bacteria. The bacteria then make human insulin, which is purified and used to treat people with diabetes. Which statement best explains why the bacteria make a human protein?
Question 15
Before a cell in a bean plant's shoot divides, it copies its DNA. During copying, one base in a gene is paired with the wrong partner and the error is not corrected. What is the most likely outcome?
Question 16
A strawberry plant makes new plants in two ways: by runners, stems that root along the ground to form new plants by mitosis, and by seeds formed after pollination. A student grows 30 plants from one parent's runners and 30 plants from the same parent's seeds, all in the same soil and light. Which result is most likely, and why?
Question 17
New mutations in the offspring of three groups of male mice
Group
Body part given X-rays
Offspring tested
Offspring with a new mutation
A
none
400
2
B
skin of the back
400
2
C
testes
400
14
Male lab mice in three groups were given a low dose of X-rays to one part of the body, or none, and then mated. Their offspring were tested for new mutations not found in either parent (table). Which claim is best supported?
Question 18
In guinea pigs, the allele for black fur (B) is dominant to the allele for white fur (b). Two guinea pigs with the genotype Bb are mated. What is the probability that one of their offspring has white fur?
Question 19
A gardener crosses a purple-flowered pea plant of unknown genotype with a white-flowered plant (pp). Purple (P) is dominant to white (p). The seeds grow into 52 purple-flowered and 48 white-flowered plants. What genotype did the purple parent have?
Question 20
In snapdragons, a plant with two red alleles has red flowers, a plant with two white alleles has white flowers, and a plant with one of each has pink flowers. Two pink-flowered plants are crossed. What is the probability that an offspring has pink flowers?
Question 21
A gardener in Queens takes cuttings from one hydrangea bush, so the new plants are genetically identical. Cuttings planted in acidic soil grow blue flowers, and cuttings planted in alkaline soil grow pink flowers. Which conclusion is best supported?
Question 22
Mass of 100 bean seeds from each plot
Seed mass (grams)
Plot A seeds (watered)
Plot B seeds (not watered)
0.3
4
15
0.4
18
38
0.5
40
32
0.6
26
12
0.7
12
3
A farm in the Hudson Valley sowed two plots with bean seeds from the same bag, a mix of the same genetic types. Plot A was watered through the summer and plot B was not. The farmer weighed 100 new seeds from each plot (table). Which conclusion is best supported?
Question 23
Red-green color blindness is caused by a recessive allele on the X chromosome. A woman with normal color vision whose father was color-blind has children with a man who has normal color vision. What is the probability that their next child is a son with red-green color blindness?
Question 24
In pea plants, tall (T) is dominant to short (t) and yellow seeds (Y) are dominant to green seeds (y); the two genes are on different chromosomes. A plant with genotype TtYy is crossed with a plant with genotype Ttyy. What fraction of the offspring are expected to be tall with green seeds?
Question 25
Cystic fibrosis is caused by a recessive allele. Two parents who do not have the condition have a child who does. What is the probability that their next child will be a carrier who does not have the condition?
Question 26
Two students each cross pairs of heterozygous fruit flies, where long wings are dominant to short wings. Student 1 counts 8 offspring: 5 long-winged and 3 short-winged. Student 2 counts 800 offspring: 603 long-winged and 197 short-winged. Which statement best explains the difference between their results?
Question 27
What is the main role of the testes in the human male reproductive system?
Question 28
Doctors advise people who are pregnant not to drink alcohol, because it can harm the development of the fetus's brain and other organs. How does alcohol in the mother's blood reach the fetus?
Question 29
Oxygen used by the cells of a fetus comes from the air that the mother breathes. Which sequence best describes how the oxygen reaches the fetus?
Question 30
A woman's ovaries release eggs normally and her uterus is healthy, but both of her oviducts are blocked. Doctors suggest in vitro fertilization (IVF): eggs are collected from her ovaries, fertilized with sperm in a lab dish, and an early embryo is placed in her uterus. Why can IVF lead to a pregnancy when natural conception cannot?
Question 31
Cells after 3 days
Cells
Drug X added
Cells on day 0
Cells on day 3
Normal skin
No
100
400
Normal skin
Yes
100
400
Tumor
No
100
1600
Tumor
Yes
100
200
In a hypothetical study, a lab grew normal skin cells and skin tumor cells, with and without drug X, starting each dish with 100 cells (table). No cells died in any dish during the 3 days. Which conclusion is best supported?
Question 32
Gene M and protein M in cells from two people
Cells tested
Gene M in the DNA
Protein M in the cells
Person 1, muscle
Present
Present
Person 1, skin
Present
Absent
Person 2, muscle
Present
Absent
In a hypothetical study, a lab tested cells for gene M, which codes for protein M, and for protein M itself (table). Person 2's gene M has exactly the same coding sequence as person 1's, but person 2 has one changed base in a noncoding stretch of DNA just before gene M. Which question do these results best raise for further study?
Question 33
In a hypothetical study, a lab inserted a jellyfish gene for a green glowing protein into the DNA of a fertilized zebrafish egg. The adult fish glowed. A glowing fish whose parents were that engineered fish and a normal fish was then mated with a normal fish: 51 of their 100 young glowed and 49 did not. Which explanation best accounts for this result?
Question 34
Human ABO blood type is controlled by one gene with three alleles: IA and IB are codominant, and both are dominant to i, so type O is ii. A parent with type A blood and a parent with type B blood have a first child with type O blood. What is the probability that their second child will have type A blood?
Question 35
Coffee during pregnancy and birth weight
Mothers' coffee
Mothers
Mean birth weight (kg)
Mothers who smoked (%)
Mean birth weight, nonsmokers only (kg)
Less than 1 cup a day
250
3.4
8
3.42
3 or more cups a day
150
3.15
40
3.38
A hypothetical study of 400 births compared mothers who drank less than 1 cup of coffee a day while pregnant with mothers who drank 3 or more cups (table). Smoking during pregnancy is known to lower birth weight. A news article says these data prove that caffeine during pregnancy lowers birth weight. Which evaluation is best supported?
Question clusters
Stem color in a class's Fast PlantsQuestion cluster · 5 credits
A biology class in Rochester grows Wisconsin Fast Plants, a quick-growing variety of the mustard plant Brassica rapa. In this stock, the allele for a purple stem (P) is dominant to the allele for a green stem (p). The class crosses a true-breeding purple-stemmed plant with a green-stemmed plant, and all 36 offspring (the F1) have purple stems. The F1 plants are then crossed with each other, and the class records the stem color of every F2 plant (table).
Stem color in the F2 generation
Stem color
Number of F2 plants
purple
184
green
56
(a) Which genotype do the F1 plants have? [1]
%
0 words · a sentence
0 words · a sentence
(e) What fraction of the purple-stemmed F2 plants are expected to have the genotype Pp? [1]
Regrowing a flatwormQuestion cluster · 4 credits
Planarians are small flatworms found under stones in streams. If a planarian is cut in two, each piece can regrow the missing parts and become a complete worm. Their bodies hold many stem cells. A student team on Long Island cut 40 planarians in half, giving 80 pieces. Group A (40 pieces) was kept in pond water. Group B (40 pieces) was first given a dose of X-rays that kills the worms' stem cells but not their specialized cells, then kept in the same pond water. After 14 days the team counted the pieces that had regrown a complete worm (table).
Pieces that regrew a complete worm after 14 days
Group
Treatment
Pieces
Pieces that regrew
A
pond water only
40
37
B
X-rays, then pond water
40
0
%
(b) Which is the independent variable in this investigation? [1]
0 words · a sentence
0 words · a sentence
Ultraviolet light and red yeast coloniesQuestion cluster · 5 credits
Baker's yeast is a single-celled fungus. On the growth medium a class in Albany used, yeast forms white colonies, but a mutation in one particular gene makes a colony red. Each colony grows from one cell. The class spread equal samples of yeast on five plates, exposed each plate to an ultraviolet (UV) lamp for a different time, and counted the colonies after 3 days (table).
Yeast colonies after different times under a UV lamp
UV time (seconds)
Colonies
Red colonies
0
520
0
15
410
2
30
300
5
45
180
7
60
90
6
%
(b) Why did the class include a plate that was given 0 seconds of UV? [1]