Chapter 10

Question 1

A cell’s DNA

Answer 1

Genome

Question 2

Discrete pieces or strands of DNA

Answer 2

chromosome

Question 3

How many complete sets or copies of the genome an organism carries in it’s cells

Answer 3

ploidy

Question 4

Contains genes in exactly the same location

Answer 4

homologues

Question 5

Gene location

Answer 5

locus

Question 6

Proteins that assist in compacting the DNA into a size that will fit in the nucleus

Answer 6

histone

Question 7

The resulting histone-DNA structures that resemble beads

Answer 7

nucleosome

Question 8

DNA when it has formed nucleosomes

Answer 8

chromatin

Question 9

Help to coil into a 30nm chromatin fiber

Answer 9

linker DNA

Question 10

A region where each original strand and its newly made copy remain firmly connected to each other

Answer 10

centromere

Question 11

Conjoined pair of chromosome and its copy

Answer 11

sister chromatid

Question 12

Near the nuclei of animal cells; an organelle

Answer 12

centrosome

Question 13

Two of these make of the centrosome and lie at right angles to each other

Answer 13

centriole

Question 14

Nuclear division (mitosis)

Answer 14

karyokinesis

Question 15

Separation of the cytoplasmic contents

Answer 15

cytokinesis

Question 16

A protein structure that appear at the centromeres of each sister chromatid

Answer 16

kinetochores

Question 17

Microtubule spindle fibers originating from the centrosomes that fully enlongate

Answer 17

mitotic spindle

Question 18

The actin filaments pull the equator inwards to form this that will eventually split the membrane in two

Answer 18

cleavage furrow

Question 19

Where the vesicles fuse from the center outward to form this in plants

Answer 19

cell plate

Question 20

Programmed cellular death

Answer 20

apoptosis

Question 21

A new membrane and cell wall constructed between two loops of DNA

Answer 21

septum

Question 22

What are the two major phases of the cell cycle and what happens in each?

Answer 22

Interphase-the cell grows and DNA replicates; Mitosis-the replicated DNA and cytoplasmic contents separate and the cell divides

Question 23

How is the genome of prokaryotes structurally different from the genome of most eukaryotes?

Answer 23

Prokaryotes have a single, circular molecule of double stranded DNA; eukaryotes have linear spiral double stranded DNA

Question 24

In humans, how is the genome arranged? How many chromosomes in one set? How many sets do humans (and most animals and plants) contain? Where do the two sets come from?

Answer 24

Humans have 23 chromosomes that are diploid. Half from mom and half from dad

Question 25

What is the difference between diploid and haploid cells?

Answer 25

Diploid have two copies while haploid have one

Question 26

Which cells in the human body are diploid and which are haploid?

Answer 26

Somatic are diploid and gametes are haploid

Question 27

How is DNA compacted to fit inside the nucleus of each cell? What are the three compaction levels of DNA?

Answer 27

DNA is would around histones which then form the nucleosome

Question 28

Associate the events of a cell life cycle with the compaction levels of the DNA.

Answer 28

Interphase-Level 1 Compaction

Question 29

What level of DNA compaction is chromatin? Chromosomes?

Answer 29

Chromatin are level 1 and chromosomes are level 3

Question 30

What are the three stages of interphase? What happens in each?

Answer 30

G1 Phase-the cell accumulates the types and numbers of molecules needed for the next step S Phase-DNA replication process occurs G2 Phase-cell replenishes its energy and makes additional proteins needed for next steps

Question 31

What types of environmental changes might affect G1?

Answer 31

Limited nutrient supply, irregular temperature, limited space

Question 32

What happens to cells that cannot pass through G1?

Answer 32

They enter the G0 phase which is a phase of inactivity

Question 33

During S phase of interphase, how are the copied strands of DNA organized? How are they held together?

Answer 33

They are held together by the centromere and are organized by sister chromatids

Question 34

What is the centrosome? What does it do? Why is this important?

Answer 34

Two centrioles that lie at right angles from one another; They are used to pull the chromosomes apart during mitosis

Question 35

What are the four phases of mitosis? What events happen at each phase?

Answer 35

Prophase, Metaphase, Anaphase, Telophase

Question 36

Cytokinesis typically overlaps with which phase(s) of karyokinesis?

Answer 36

telophase

Question 37

Describe events that result in the cleavage of animal cells into two daughter cells during cytokinesis. How does this process differ in plant cells?

Answer 37

A contractile ring composed of actin filaments forms around the cell just inside the plasma membrane at the site of the metaphase plate. The actin filaments pull the equator inward, forming a cleavage furrow that eventually cleaves the membrane in two Plants form a cell plate

Question 38

Name several events external to the cell that might regulate cell division.

Answer 38

Death of nearby cells(inhibit); Presence of Growth Promoting Hormone (initiate); Crowding of Cells (inhibition); Growing size of the cell (initiate

Question 39

How many internal checkpoints occur during the cell cycle? Between which phases and events do each of them occur?

Answer 39

3; near end of G1, G2/M transition, during M

Question 40

What types of things are the internal checkpoints examining?

Answer 40

Adequate reserves, sufficient cell size, Genomic DNA damaged, all chromosomes replicated, kinetochores of each pair of sister chromatids firmly anchored to at least two spindle fibers, each sister chromatid in the pair bonded to spindle fibers from opposite poles of the cell

Question 41

What two specific groups of proteins are considered to be positive regulator molecules of the cell cycle?

Answer 41

Cyclins and CDK (cyclin dependent kinases)

Question 42

How do the cyclins and CDKs interact to regulate the cell cycle?

Answer 42

Cyclins are the main regulatory molecules that determine the forward progress of the cell cycle Cyclins regulate the cell cycle only when bound to CDKs

Question 43

Name two specific proteins are considered to be negative regulator molecules.

Answer 43

P53 and p21

Question 44

How do negative regulator molecules influence positive regulator molecules?

Answer 44

Halt the cell cycle when problematic conditions arise

Question 45

Understand and describe the role of the p53 protein in regulating cell cycle progression.

Answer 45

Halts the cell cycle and recruits enzymes to repair the DNA; can trigger apoptosis to prevent duplication of damaged chromosome

Question 46

Understand how mutations lead to cancerous growth (or not).

Answer 46

If mutations occur in the coding region, this can lead to cancer; if it is in a non-coding region, there is no functional change

Question 47

What are proto-oncogenes? What are oncogenes?

Answer 47

proto-oncogenes are normal genes that code for positive cell cycle regulator while oncogenes are mutated genes that lead to an unnatural increase in the rate of cell cycle progression

Question 48

What are tumor suppressor genes? Give an example of a tumor suppressor gene.

Answer 48

genes that code for negative cell cycle regulators; p53- if mutated, cancer is likely to form (more than 1/2 of cancer has mutation of p53)

Question 49

How do prokaryotic cells divide? Name some differences between prokaryotic and eukaryotic cell division.

Answer 49

binary fission, can replicate both directions and creates a septum, there is also no histones or nucleosomes