What Is Life? A Guide to Biology

Jay Phelan

Chapter 6

Chromosomes and Cell Division - all with Video Answers

Educators

Chapter Questions

Problem 1

How are breathing and cellular respiration similar? How are they different?

Aditya Sood

Aditya Sood

Numerade Educator

Problem 1

Which of the following statements about telomeres is incorrect?

a) They function like a counter, keeping track of how many times a cell has divided.
b) At birth, they are long enough to permit approximately 50 cell divisions in most cells.
c) They are slightly shorter in prokaryotic cells than in eukaryotic cells.
d) They function like a protective cap on chromosomes.
e) They contain no critical genes.

Jenny Wu

Numerade Educator

Problem 2

How do chemiosmotic phosphorylation and substrate-level phosphorylation each generate ATP? In which pathways does each occur?

Emily Himsel

Numerade Educator

Problem 2

Prokaryotic cells can divide via:
a) mitosis.
b) binary fission.
c) meiosis.
d) both mitosis and binary fission.
e) None of the above.

Jenny Wu

Numerade Educator

Problem 3

In multicellular organisms, cells that undergo mitotic division but not meiotic division are called ______ cells.
a) somosis
b) skin
c) interphase
d) somatic
e) germ

Jenny Wu

Numerade Educator

Problem 3

How does aerobic respiration yield so much ATP from each glucose molecule, compared with glycolysis alone?

Aditya Sood

Numerade Educator

Problem 4

The ______ marks the break in the cell cycle between the end of mitosis and beginning of the DNA synthesis stage.
a) mitotic phase
b) synthesis phase
c) Gap 2 phase
d) Gap 1 phase
e) None of the above.

Jenny Wu

Numerade Educator

Problem 4

Cite a reaction or pathway that occurs in each of the following locations:
a. cytoplasm
b. mitochondrial matrix
c. inner mitochondrial membrane
d. intermembrane compartment

Christina Sorrentino

Christina Sorrentino

Numerade Educator

Problem 5

Health-food stores sell a product called "pyruvate plus," which supposedly boosts energy. Why is this product unnecessary? What would be a much less expensive substitute that would accomplish the same thing?

Aditya Sood

Numerade Educator

Problem 5

Mitosis results in:
a) daughter cells with twice as much genetic material as the parent cell and a unique collection of alleles.
b) eight daughter cells.
c) daughter cells with the same number and composition of chromosomes.
d) gametes.
e) daughter cells with the same number of chromosomes but different combinations of alleles.

Jenny Wu

Numerade Educator

Problem 6

At what point does $\mathrm{O}_{2}$ enter the energy pathways of aerobic respiration? What is the role of $\mathrm{O}_{2} ?$ Why does respiration stop if a person cannot breathe? What happens if cellular respiration stops?

Aditya Sood

Numerade Educator

Problem 6

Using a light microscope, it is easiest to see chromosomes:
a) during mitosis and meiosis, because the condensed chromosomes are thicker and therefore more prominent.
b) during interphase, when they are concentrated in the nucleus.
c) in the mitochondria, because the chromosomes are circular.
d) during asexual reproduction.
e) during interphase, because they are uncoiled and have a more linear structure.

Jenny Wu

Numerade Educator

Problem 7

In a properly functioning mitochondrion, is the $\mathrm{pH}$ in the matrix lower than, higher than, or the same as the pH in the intermembrane compartment? If you apply one or more poisons described in this chapter's Apply It Now box, how does your answer change?

Josee Pacheco

Numerade Educator

Problem 7

The division of the cytoplasm during cell division is referred to as:
a) cytoplasm splicing.
b) cytokinesis.
c) vegetative growth.
d) cytodivision.
e) hybridization.

Jenny Wu

Numerade Educator

Problem 8

A chemical works as a disinfectant by poking holes in bacterial cell membranes. Why would this stop the cells from making ATP? Why would the inability to make ATP kill a cell?

Aditya Sood

Numerade Educator

Problem 8

Which of the following statements about tumors is incorrect?
a) Benign tumors pose less of a health risk than do malignant tumors.
b) Malignant tumors shed cancer cells that can spread to other parts of the body.
c) Tumors are caused by excessive cell growth and division.
d) Cancer cells from malignant tumors can travel to other parts of the body in a process called metastasis.
e) They contain cells with abnormally high contact inhibition.

Jenny Wu

Numerade Educator

Problem 9

Describe the energy pathways that are available for cells living in the absence of $\mathrm{O}_{2}$.

Aditya Sood

Numerade Educator

Problem 9

During meiosis but not during mitosis:
a) haploid gametes are produced that are all identical in their allelic composition.
b) division of the cytoplasm occurs.
c) chromosomes line up in the center of the cell during metaphase.
d) genetic variation among the daughter cells is increased.
e) two identical daughter cells are produced.

Jenny Wu

Numerade Educator

Problem 10

Ben decides to bake bread. The recipe says to dissolve yeast in a mixture of sugar and hot water. Shortly after he does so, the mixture begins to bubble. What is happening? How would the outcome change if Ben forgets to add the sugar?

Willis James

Numerade Educator

Problem 10

Sister chromatids are:
a) the result of crossing over.
b) identical molecules of DNA resulting from replication.
c) homologous chromosomes.
d) produced in meiosis but not in mitosis
e) single-stranded.

Jenny Wu

Numerade Educator

Problem 11

How are photosynthesis, glycolysis, and cellular respiration interrelated?

Aditya Sood

Numerade Educator

Problem 11

Which of the following events does not occur during prophase I of meiosis?
a) Spindle fibers form.
b) Homologous pairs of chromosomes align at the metaphase plate.
c) Homologues come very close together.
d) Crossing over occurs between sister chromatids.
e) Chromosomes condense.

Jenny Wu

Numerade Educator

Problem 12

A student runs 5 kilometers each afternoon at a slow, leisurely pace. One day, she runs $2 \mathrm{km}$ as fast as she can. Afterward she is winded and feels pain in her chest and leg muscles. She thought she was in great shape! What, in terms of energy metabolism, has she experienced?

William Oh

Numerade Educator

Problem 12

Which of the following is the best way to distinguish male from female?
a) Males are larger.
b) Males are more brightly colored.
c) Males produce motile gametes.
d) Males are more aggressive.
e) All of the above statements are correct.

Jenny Wu

Numerade Educator

Problem 13

Explain the fact that species as diverse as humans and yeasts use the same biochemical pathways to extract energy from nutrient molecules.

William Oh

Numerade Educator

Problem 13

A potential disadvantage of asexual reproduction is that:
a) it increases the time required to find a mate.
b) it allows perpetuation of a population even when the members are isolated.
c) it allows population size to increase rapidly.
d) it produces genetically uniform populations.
e) it requires additional rounds of meiosis which is energetically much more costly than mitosis.

Jenny Wu

Numerade Educator

Problem 14

A seed is a plant embryo packaged with a food supply. Soaking a seed in water prompts the embryo to begin metabolizing its food supply to fuel its growth. Suppose that Anna has 50 soaked seeds. She boils half of them, killing their embryos, and lets them return to room temperature. She then places the dead seeds in one closed container and live seeds in another. If she later measures the temperature in the two containers, will they be different? Explain your answer.

Christina Sorrentino

Christina Sorrentino

Numerade Educator

Problem 14

Which of the following is not a method of chromosomal sex determination that occurs in nature?
a) In birds, the mother's sex chromosomes determine the sex of the offspring.
b) In sea turtles, eggs laid in hot sand become females and eggs laid in cooler sand become males
c) In humans, the presence of a Y chromosome makes an individual male, even if he also possesses two $X$ chromosomes.
d) In bees, the eggs that the queen allows to be fertilized become females and the eggs she doesn't fertilize become males.
e) All of the above are naturally occurring examples of sex determination.

Jenny Wu

Numerade Educator

Problem 15

Birds and mammals are endotherms: they maintain a constant internal body temperature no matter whether the environment is cold or hot (within limits, of course). An endotherm that gets too cold will increase its metabolic rate to generate heat. An ectothermic animal such as a reptile, on the other hand, allows its body temperature to fluctuate with the environment. If you own a pet rat and a pet snake of equal weight, which will require more food and why?

Lottie Adams

Numerade Educator

Problem 15

A karyotype reveals:
a) the shape of the spindle.
b) 23 pairs of chromosomes.
c) the number, shapes, and sizes of chromosomes in an individual cell.
d) the sex chromosomes but not the non-sex chromosomes
e) the non-sex chromosomes but not the sex chromosomes

Jenny Wu

Numerade Educator

Problem 16

What type of chromosomal abnormality leads to the phenotype known as Down syndrome?
a) trisomy 21
b) monosomy 21
c) monosomy 22
d) trisomy 22
e) disomy 21

Jenny Wu

Numerade Educator

Problem 17

Nondisjunction:
a) is the unequal division of the genetic material during cell division.
b) occurs during meiosis but not mitosis.
c) occurs in males but not females among mammals, and in females but not males among birds.
d) leads to a missing chromosome or extra chromosome.
e) Both a) and $d$ ) are correct.

Jenny Wu

Numerade Educator

Problem 18

Of all the varying types of sex chromosome abnormalities, one possibility—that of an individual having one Y but no X—has never been reported. Which of the following statements is the most likely reason that medical researchers have yet to report a person having a karyotype with one Y and no X?
a) There is no meiotic event that could produce an egg that does not have an X chromosome.
b) Individuals are probably born with this karyotype; however, because the phenotypic abnormalities caused are so slight, they live out their lives normally and are unaware of this genetic anomaly.
c) The $Y$ chromosome needs the $X$ chromosome to be present in the cell in order for its genes to be expressed.
d) The X chromosome contains genes that are unrelated to sex determination and are essential for life.
e) Our current technology for karyotyping would not reveal such an abnormality.

Jenny Wu

Numerade Educator