Chapter 8 - Cellular Reproduction

Question 1

Why do normal, healthy cells divide?

Answer 1

1. growth and development
2. cell replacement or renewal
3. to heal wounds or repair damage

Question 2

What is a chromosome?

Answer 2

compact structure that contains DNA

Question 3

What is a homologous chromosome?

Answer 3

chromosome with an identical partner

Question 4

What is a centromere?

Answer 4

portion of a chromosome which keeps replicated chromatids together, where sister chromatids are joined together

Question 5

What is a chromatid?

Answer 5

one of the two replicated strands of a duplicated chromosome (joined by a centromere)

Question 6

What are spindle fibers?

Answer 6

microtubules that attach to the centromere and move the chromosomes around during cell division

Question 7

How do cells divide?

Answer 7

before division, cells make a copy of their contents (each new cell much have same amount of organelles, DNA, and cytoplasm as original) –> divides into two daughter cells

Question 8

What is the cell cycle?

Answer 8

ordered sequence of stages through which a cell progresses in order to divide during it’s life

Question 9

Is interphase a phase of cell division?

Answer 9

NO

Question 10

What are the steps of Interphase?

Answer 10

G0: cell cycle arrest
G1: “macromolecule synthesis” - cell contents (excluding chromosomes) are duplicated, DNA in nucleus is doubled
S: “synthesis” - cell replication, each of the 46 chromosomes are duplicated
G2: preparation for mitosis, cell “double checks” the duplicated chromosomes for error, makes repairs

Question 11

What are the stages of Mitosis?

Answer 11

1. Prophase
2. Metaphase
3. Anaphase
4. Telophase

Question 12

What is Prophase?

Answer 12

“Prepare to divide,” or “Presence of chromosomes”

• nuclear membrane and nucleolus disappear
• chromatin fibers coil and chromosomes thicken/can be seen by microscope
• spindle fibers also begin to appear

Question 13

What is Metaphase?

Answer 13

“Middle of the cell”

• centromeres of the chromosomes arrange themselves into equatorial (linear) plane at middle of cell
• homologous chromosomes do not “synapse” or line up side-by-side (if they did, daughter cells would be identical)

Question 14

What is Anaphase?

Answer 14

“move Away”

• the sister chromatids are pulled by the spindle fibers and separate and move to opposite ends of cell
• microtubules not attached to chromosomes lengthen and push poles further apart/elongating the cell

Question 15

What is Telophase?

Answer 15

“Two separate nuclei”

• chromosomes disappear, nuclear membrane reappears
• still connected by cytoplasm
• DNA division is complete

Question 16

What is Mitosis?

Answer 16

duplicated chromosomes are separated, then two daughter nuclei form

Question 17

What is Cytokinesis?

Answer 17

cytoplasmic contents divided in half by formation of a new cell membrane (daughter cells contain full complement of organelles and DNA)

Question 18

What happens during mitosis?

Answer 18

1. chromosomes condense, nuclear membranes break down
2. chromosomes tethered to spindle fibers that direct movement
3. chromosomes aligned down the middle of the dividing cell
4. duplicated chromosomes are pulled to opposite sides of the cell
5. nuclear membrane reforms around each daughter nucleus

Question 19

What is a cleavage furrow?

Answer 19

where the cells “furrow”/pinch and divide

-animal cells must create new cell plate –> leads to formation of new cell wall

Question 20

What is a karyotype?

Answer 20

a picture where homologous chromosomes can be lined up and analyzed

Question 21

What is a diploid?

Answer 21

2 sets of chromosomes (one from mom, one from dad), 2n

Question 22

What kind of cells are sex cells?

Answer 22

haploid

Question 23

What kind of cells are autosomal cells?

Answer 23

diploid

Question 24

What are gametes?

Answer 24

haploid sex cells, specialized reproductive cells (egg + sperm)

Question 25

What is a zygote?

Answer 25

result when haploid sperm cell fertilizes haploid eggs cell | -2 copies of every gene

Question 26

What are the stages of Meiosis?

Answer 26

1. Meiosis I 2. Synapsis 3. Meiosis II * PMAT occurs twice

Question 27

What happens in Meiosis I?

Answer 27

we end up with two daughter cells with the homologous pairs pulled apart

Question 28

What happens in Synthesis?

Answer 28

occurs when the replicated homologues pair up (only in meiosis)

Question 29

What happens in Meiosis II?

Answer 29

pulling apart of sister chromatids | -pulls the single duplicated chromosomes into separate chomatids and we end up with 4 haploid gametes

Question 30

What happens when a cell doesn't pass a checkpoint?

Answer 30

- irreparable damage | - apoptosis: programmed cell death

Question 31

What is apoptosis?

Answer 31

- programmed cell death - also part of normal development, scheduled death of soft tissue cells that form "web" between digits in utero, tadpoles lose tails when maturing into a frog

Question 32

What is asexual reproduction?

Answer 32

reproduction without fertilization of an egg by sperm | -offspring inherits all chromosomes from a single parent

Question 33

What is chromatin?

Answer 33

fibers composed of roughly equal amounts of DNA and protein molecules, make up chromosomes -helps organize and regulate access to DNA during DNA replication, expression, and cell division

Question 34

What is a nucleosome?

Answer 34

DNA wound around histone molecules

Question 35

What are sister chromatids?

Answer 35

two copies of identical genes within chromosomes

Question 36

What is interphase?

Answer 36

the period when a cell performs its normal functions within an organism (ex. stomach lining making/releasing molecules that aid in digestion) - roughly doubles everything in its cytoplasm - 90% of cell cycle

Question 37

What s a tumor?

Answer 37

abnormal mass of body cells

Question 38

What is metastasis?

Answer 38

spread of cancer cells beyond original site through lymph/blood vessels to other parts of the body

Question 39

What happens in Prophase I?

Answer 39

homologous chromosomes pair up and exchange segments | -"cross over" to rearrange genetic information

Question 40

What happens in Metaphase I?

Answer 40

pairs of homologous chromosomes line up - sister chromatids still attached at centromeres - poised to move to opposite ends of cell because microtubules come from opposite centromeres

Question 41

What happens in Anaphase I?

Answer 41

pairs of homologous chromosomes split up | -in contrast to mitosis, sister chromatids stay intact (just separated from homologous partners)

Question 42

What happens in Telophase I/Cytokinesis?

Answer 42

Two haploid cells form, chromosomes are still doubled | -each pole has haploid chromosome set

Question 43

What happens in Prophase II?

Answer 43

spindle forms and moves the chromosomes toward the middle of the cell

Question 44

What happens in Metaphase II?

Answer 44

the chromosomes are aligned as they are in mitosis, with the microtubules attached to the sister chromatids of each chromosome coming to opposite poles

Question 45

What happens in Anaphase II?

Answer 45

the centromeres of sister chromatids separate and the sister chromatids of each pair move toward opposite poles of the cell

Question 46

What happens in Telophase II?

Answer 46

nuclei form at the cell poles --> cytokinesis (4 haploid daughter cells each with single chromosomes)

Question 47

How is DNA organized in eukaryotic cells?

Answer 47

DNA wrapped around proteins in complex called chromatin

Question 48

What are examples of haploid cells?

Answer 48

egg and sperm gametes

Question 49

Mitosis vs. Meiosis: | What kinds of cells?

Answer 49

Mitosis: all cells Meiosis: just gamete-producing cells

Question 50

Mitosis vs. Meiosis: | Does synapse occur?

Answer 50

Mitosis: no Meiosis: yes

Question 51

Mitosis vs. Meiosis: | How many daughter cells produced?

Answer 51

Mitosis: 2 daughter cells Meiosis: 4 daughter cells

Question 52

Mitosis vs. Meiosis: | Is the original cell haploid or diploid?

Answer 52

Mitosis: either haploid or diploid Meiosis: must be diploid

Question 53

Mitosis vs. Meiosis: | Are the daughter cells haploid or diploid?

Answer 53

Mitosis: haploid or diploid depending on original cell Meiosis: haploid

Question 54

Mitosis vs. Meiosis: | What is the genetic content of the daughter cell in relation to the original cell?

Answer 54

Mitosis: content is identical Meiosis: content differs

Question 55

Mitosis vs. Meiosis: | How does the content compare between daughter cells?

Answer 55

Mitosis: identical Meiosis: different

Question 56

What are cell cycle checkpoints?

Answer 56

points that ensure that each stage of the cell cycle is completely accurately

Question 57

What happens at the G1-S checkpoint?

Answer 57

Is there a signal to divide? Is cell size adequate? | Is there enough raw material to replicate DNA?

Question 58

What happens at the G2-M checkpoint?

Answer 58

Are chromosomes fully replicated? Is DNA damage repaired?

Question 59

What happens at the Mid-Mitosis checkpoint?

Answer 59

Are chromosomes aligned properly for separation of chromatids?