Biology 101: Intro to Biology Ch 8. Cell Growth & The Process of Cell Division

Genome

The total of the entire DNA in a cell

Chromosomes

a discrete structure of DNA; single molecule of DNA; represents specific subset of information in genome

Gamets

sex cells; egg cells (female) or sperm cells (male); 23 n

Homologous Chromosomes

also known as homologs; the two different versions of the chromosomes

Diploid

Two haploid sets of chromosomes; has 46 or 2n; two sets of chromosomes

Haploid

Approximately one chromosome complement

A mutation occurs on a chromosome in a sperm gamete. Which of the following might explain why diploidy may prevent some of the offspring from developing a disease associated with this mutation?

1. All diseases come from changes in multiple chromosomes.

2. Only one homologous chromosome must have the mutation for any disease to be manifest.

3. Only one homologous chromosome has the mutation (the sperm) but not the other (the egg) so the normal genes are present.

4. It is always necessary for both homologous chromosomes to have the defective gene in order for the disease to develop.

Only one homologous chromosome has the mutation (the sperm) but not the other (the egg) so the normal genes are present.

At conception, your mother contributed a gene that encoded for the sickle hemoglobin (hemoglobin S), while your father contributed the same gene that encoded for normal hemoglobin (hemoglobin A). Which of the following denotes the DNA structures which carry these variants?

1. Analogs and homologous chromosomes.

2. Homologs and homologous chromosomes.

3. Homologs, chromatids, and homologous chromosomes

4. Chromatids.

Homologs and homologous chromosomes.

If the diploid chromosome count in humans is 46, how many pairs of homologous chromosomes are there?

1. 46

2. 92

3. 45

4. 23

23

A rabbit is a diploid organism. Its egg cell has 22 chromosomes. How many chromosomes can be found in a rabbit's neuron cell?

1. 48

2. 11

3. 44

4. 22

44

Choose the smallest correct answer.

In general, the loss of _____ chromosome(s) is usually considered a lethal event.

1. 3

2. 4

3. 2

4. 1

1

DNA

The storehouse of information in a cell; is organized into chromosomes

The Structure of Chromosomes

has 3 billion bases

Histones

Proteins that help package the DNA more efficiently

Genes

A distinct unit of DNA that can make protein or RNA

Non-Coding DNA

DNA that does not make protein; also known as “junk DNA;” serves a number of purposes; both structurally and functionally

The combination of multiple histones and DNA is called what?

1. Gene

2. Noncoding

3. Chromatin

4. Histone

Chromatin

Place the following terms in order building out from the most basic informational subunit to the entire genetic unit:

I. Chromosome

II. DNA

III. Chromatin

IV. Nucleosome

1. II, IV, III, I

2. II, III, IV, I

3. III, IV, II, I

4. IV, III, II, I

5. II, I, IV, III

II, IV, III, I

A distinct unit of DNA that produces a protein that provides the functionality a cell needs is _____.

1. histone

2. genome

3. chromatin

4. gene

gene

Which of the following roles in the cell could non-coding DNA perform?

I. Provide structural support at the end of chromosomes.

II. Encode a protein that will play a significant role in cell division.

III. Serve functional purposes.

1. III

2. I and III

3. I and II

4. I

5. II

I and III

_____ is a protein that plays a central role in DNA folding.

1. Nucleosome

2. Chromatin

3. Histone

4. Gene

Histone

The Cell Cycle

The sequence of events through which a cell progresses during its lifetime

G1 Phase

• Cell Growth

• Protein Synthesis

• Cell metabolism

• Preparations for S Phase

Not Dividing

preparing for cell division

Chromatids

one of two copies of a chromosome produced when a chromosome is replicated

G2 Phase

• Protein Synthesis

• Further Cell Growth

• Proteins needed for Cell Division (i.e. microtubules) are produced

Mitosis

How a cell equally divides chromosome copies made in S Phase; the process of separating the nuclear DNA into identical complements for the new daughter cells

Cytokineses

Cytoplasm and organelles are divided evenly between the two new cells

All of the following occur during interphase EXCEPT:

1. Protein synthesis

2. Cell division

3. S phase

4. Cell growth

5. Chromosome replication

Cell division

A _____ is one of two copies of a replicated chromosome

1. Chloroplast

2. Chromatid

3. Chromatin

4. Chromomere

5. Centromere

Chromatid

A chromosome consists of two chromatids for AT LEAST part of all of these steps EXCEPT:

I. G1

II. G2

III. M Phase

IV. S Phase

1. II

2. I

3. IV

4. III

I

Which of the following statements is TRUE?

1. Preparation for S phase occurs during G2.

2. Chromosome replication occurs during S phase.

3. Cytokinesis is the third step in interphase.

4. The non-dividing state of the cell cycle is called mitosis.

5. M phase occurs between G1 and S phase.

Chromosome replication occurs during S phase.

Place the following steps in the cell cycle into the order in which they occur.

I. G1

II. G2

III. S phase

IV. M phase

1. I, III, II, IV

2. II, III, I, IV

3. I, II, IV, III

4. I, IV, II, III

5. IV, I, II, III

I, III, II, IV

Cell Division

each new daughter cell receives a full complement of genomic DNA

DNA

3,000,000,000 bases

6 Microns

.0002 inches

2 Meters

7 meters

Chromosome Condensation

The process in which chromosomal DNA is packaged more compactly in preparation for mitosis

Karyogram

A picture of the complete set of homologous chromosomes of an organism

Karyotype

The number and appearance of chromosomes in an organism

A pathologist issued a report on the karyotype of a patient. A doctor might use this information to identify:

1. the patient's biological sex

2. the patient's ethnicity.

3. an abnormal gene.

4. an abnormal protein.

5. the patient.

the patient's biological sex

The process in which the duplicated DNA of a diploid cell is separated into two daughter cells is called:

1. Prophase

2. Prometaphase

3. Metaphase

4. Meiosis

5. Mitosis

Mitosis

Which of the following statements is true of chromatin?

1. Chromatin is a protein composed of histones

2. Chromatin involves interaction between DNA and proteins

3. Chromatin structure is completely disorganized

4. Chromatin is located within the cytoplasm

5. Chromatin is never packaged into more compact structures

Chromatin involves interaction between DNA and proteins

Chromosome condensation:

1. Refers the number and appearance of the chromosomes of an organism

2. Occurs during G1 phase of cell growth when access to the DNA is not required

3. Is an organized picture of all of the mitotic chromosomes, which can be used by scientists to study the karyotype.

4. Is the process of separating the nuclear DNA into identical complements for the new daughter cells

5. Packages chromosomal DNA more compactly in preparation for mitosis

Packages chromosomal DNA more compactly in preparation for mitosis

A picture in which all of the homologous chromosomes of an organism have been stained and organized is called a(n):

1. Chromogram

2. Karyogram

3. Genotype

4. Ultrasound

5. Chromosomal panel

Karyogram

Sister Chromatids

Copies of the same chromosome

Centromere

Physical location where sister chromatids are held together

Chromosomal Arm

Each segment of DNA above and below the centromere

Telomere

Portion of chromosomal tip…which protects from degradation

A chromosome may be defined as:

1. A diploid organisms that has two copies of itself

2. A single strand of DNA, which represents a specific subset of the information in the genome

3. A single molecule of DNA, which represents a specific subset of the information in the genome

4. A physical location along the chromosome where sister chromatids are held together throughout most of cell division

A single molecule of DNA, which represents a specific subset of the information in the genome

If a human has forty-six chromosomes, what is the maximum number of chromatids that could be found in a cell in a normal human body?

1. 46

2. 4

3. 23

4. 12

5. 92

92

Which of the following are primary functions of the centromere?

I. Hold sister chromatids together

II. Protect chromosomes

III. Repair DNA damage

1. I

2. I and II

3. III

4. II and III

5. II

I

How many sister chromatids can exist for a chromosome during mitosis?

1. 23

2. 2

3. 46

4. 92

5. 4

2

Loss of one of the telomeres of a chromosome could result in which of the following?

I. Chromosome shortening

II. Loss of genomic information

III. An increase in chromosome number

I, II and III

1. I

2. II

3. III

4. I and II

I and II

Microtubles

A rope-like component of the cytoskeleton

Mitotic Spindle

a structure composed of microtubules which segregates chromosomes into daughter cells

Centrosome

An organelle that serves as a microtubule organizing center during cell division

Spindle Pole

The region of the cell where centrosome is located and toward which the chromosomes will move

Astral Microtubule

a short microtubule emanating from the centrosome to position the spindle apparatus

Kinetochore Microtubule

a microtubule which attaches to the kinetochore and positions the chromosomes

The protein structure on a chromosome to which microtubules may attach is a

1. Chromatin

2. Telomere

3. Centrosome

4. Arm

5. Kinetochore

Kinetochore

Part of the cell cytoskeleton, these are a major component of the mitotic spindle.

1. Kinetochore

2. Chromosome

3. Microtubules

4. Centrosome

5. Spindle poles

Microtubules

The primary type of microtubule that positions the chromosome in preparation for mitosis is

1. Astral microtubule

2. Tethering microtubule

3. Kinetochore microtubule

4. Polar microtubule

Kinetochore microtubule

This emanates from the centrosome to position the mitotic spindle within the cell.

1. Spindle pole

2. Centromere

3. Astral microtubule

4. Kinetochore microtubule

Astral microtubule

The organelle that serves as a microtubule organizing center during cell division is the

1. Cytoskeleton

2. Centromere

3. Centrosome

4. Chromosome

5. Chromomere

Centrosome

Interphase

DNA replication occurs and the centrosomes duplicate

Prophase

Chromosomes condense, centrosomes move to opposite sides of the cell and the mitotic spindle begins to assemble

Prometaphase

• Prometaphase is the second step of mitosis

• Nuclear envelope breaks down

• Chromosomes attach to the mitotic spindle

• Chromosomes orient toward the metaphase plate

Metaphase

• Metaphase is the third step in mitosis

• All chromosomes are aligned at metaphase plate

• Metaphase plate is an imaginary line in the middle of the cell halfway between the spindle poles, where chromosomes align during mitosis

• Metaphase plate is also sometimes referred to as Equatorial Plate

Anaphase

• Anaphase is the fourth step in mitosis

• Physical connection between sister chromatids is severed allowing chromatids to move toward their spindle pole

Telophase

• Telophase is the fifth and final step in mitosis

• Mitotic spindle breaks down

• Chromosomes uncoil to diffuse interphase state

• Nuclear membrane reforms

Chromosomes are maximally condensed at this step.

1. Prometaphase

2. Metaphase

3. Prophase

4. Interphase

5. Anaphase

Metaphase

Organize these steps in the order in which they would occur during cell division.

1. Prophase, prometaphase, metaphase, anaphase, telophase

2. Anaphase, interphase, metaphase, prometaphase, prophase, telophase

3. Prometaphase, interphase, prophase, metaphase, anaphase, telophase

4. Interphase, prometaphase, prophase, metaphase, anaphase, telophase

5. Interphase, prophase, prometaphase, anaphase, metaphase, telophase

Prophase, prometaphase, metaphase, anaphase, telophase

Chromosome de-condensation occurs during this step.

1. Telophase

2. Prometaphase

3. Metaphase

4. Prophase

5. Anaphase

Telophase

During this step, the nuclear membrane breaks down.

1. Prophase

2. Anaphase

3. Prometaphase

4. Metaphase

5. Interphase

Prometaphase

Which of the following events occur during prophase?

I. Centrosome duplication

II. Centrosome movement to the spindle poles

III. Centrosome organization of the spindle apparatus

1. I

2. I and II

3. I, II and III

4. I and III

5. II and III

I, II and III

Contractile Ring

A ring of actin filaments located below the cell membrane which constricts the middle of a dividing cell

Cell Plate

The new cell wall, which forms between dividing plant cells

Segregation of cytoplasmic content in cell division occurs during _____.

1. Prometaphase

2. Metaphase

3. Cytokinesis

4. Prophase

Cytokinesis

Which of the following structures does NOT participate in the cell division of a sunflower cell?

I. Contractile ring

II. Cell plate

III. Vesicle

1. III only

2. I and III

3. II and III

4. I only

I only

All of the following statements are correct EXCEPT:

1. Both plant and animal cells undergo cytokinesis.

2. The components of the cell plate formed during cytokinesis are produced by the mitochondrion.

3. Cytokinesis is the process in which the cytoplasmic content of the cell is divided into two new cells.

4. Cytokinesis occurs after the cells' content has been duplicated.

The components of the cell plate formed during cytokinesis are produced by the mitochondrion.

The new cell wall which forms between dividing plant cells during cytokinesis is known as the _____.

1. cell platter

2. cell moat

3. cell shield

4. cell plate

cell plate

During animal cell division, actin filaments organize into the _____.

1. Contractile ring

2. Plasma membrane

3. Mitotic spindle

4. Cell plate

Contractile ring

Asexual Reproduction

a form of reproduction from a single parent based on mitosis

Sexual Reproduction

A form of reproduction where offspring are produced from union of gametes from two genetically different parents

Gamete

A specialized sex cell produced by each parent for sexual reproduction

Meiosis

a specialized type of cell division which procedures gamete cells for sexual reproduction

What genetic advantage does sexual reproduction have over asexual reproduction?

1. All individuals share the same genetic weaknesses.

2. Genetic variations are not possible and ensure exact clones.

3. Genetic variations are possible to promote survival of the species.

4. Asexual reproduction does not require a mate.

Genetic variations are possible to promote survival of the species.

Which of the following characteristics is unique to meiosis?

1. DNA replication prior to cell division.

2. Chromosome condensation.

3. Reduction of the number of chromosomes in the cell by half.

4. Microtubules in the gametes.

Reduction of the number of chromosomes in the cell by half.

Which of the following statements about asexual reproduction is NOT true?

1. It produces clones of the original cell.

2. It is a seldom used form of reproduction.

3. It does not improve genetic variation.

4. It does not require a mate for reproduction.

It is a seldom used form of reproduction.

Which of the following statements about gametes are true?

I. In sexual reproduction, each parent provides genetic material for the formation of either an egg or a sperm cell.

II. Gametes are produced by mitosis.

III. If a sexually reproducing organism is diploid, the gametes are haploid.

1. II and III

2. I, II and III

3. I and III

4. I and II

I and III

Which of the following is true about both meiosis and mitosis?

1. DNA replication precedes cell division.

2. The primary goal of both processes is to reduce the number of chromosomes in the cell by half

3. Offspring result with twice the number of chromosomes.

4. Both processes yield a set of diploid offspring.

DNA replication precedes cell division.

Homologous Recombination or Crossing Over

A process in which genetic material is exchanged between homologous chromosomes

Meiosis I

The first of the two divisions in meiosis, during which homologous chromosomes are seperated

Meiosis II

the second of the two divisions in meiosis, during which sister chromatids are separated

If the cell of a diploid organism (2n = 6) undergoes meiosis, how many different chromosome homologs are present in each daughter cell at the end of meiosis I?

1. 18

2. 24

3. 6

4. 3

5. 12

3

If the cell of a diploid organism (2n = 6) undergoes meiosis, how many chromosomes are present in each daughter cell at the end of meiosis II?

1. 6

2. 3

3. 24

4. 18

5. 12

3

If the cell of a diploid organism (2n=4) undergoes mitosis, how many chromosomes are present in each daughter cell?

4

Which of the following is/are consequences of meiotic recombination?

I. Increased genetic diversity

II. Exchange of parts of homologous chromosomes

III. Stabilization of chromosomes at the metaphase plate

1. I

2. I and III

3. II and III

4. I, II and III

5. I and II

I, II and III

After meiosis I, each daughter cell contains:

1. one homolog of each homologous pair of chromosomes.

2. four chromatids of each chromosome.

3. one chromatid of each homolog.

4. one chromosome of each homolog.

5. one chromatid of each chromosome.

one homolog of each homologous pair of chromosomes.