Cell Division for Development, Growth, and Maintenance in Multicellular Organisms (Mitosis)

Question 1

What are three main reasons for which cells need to divide?

Answer 1

reproduction, development (including growth), maintenance

Question 2

What does maintentance involve?

Answer 2

repairing damage, tissue renewal…

Question 3

What is growth?

Answer 3

increase in number of cells

Question 4

What are ways cells develop other than growth?

Answer 4

differentiation, morphogenesis…

Question 5

What is the difference between stem cells and most other cells?

Answer 5

most cells differentiate while stem cells don’t

Question 6

What happens when a cell differentiates?

Answer 6

becomes specialized, develops into a certain type of cell

Question 7

What makes a cell lose the ability to become other kinds of cells?

Answer 7

differentiation

Question 8

What cells remain plastic?

Answer 8

stem cells

Question 9

What does “plastic” mean in terms of cells?

Answer 9

ability to generate different types of cells

Question 10

What are two special characteristics of stem cells?

Answer 10

self-renewal and potency

Question 11

What does self-renewal mean?

Answer 11

cells continue to divide and divide without differentiating

Question 12

What is potency?

Answer 12

capacity to produce cells that differentiate into specific cell types

Question 13

What is an extreme case of tissue renewal?

Answer 13

limb regeneration in animals

Question 14

What are some animals that can regenerate their limbs?

Answer 14

starfish, crabs, salamanders

Question 15

What are the 4 types of stem cells?

Answer 15

• totipotent
• pluripotent
• multipotent
• unipotent

Question 16

What types of cells can totipotent stem cells form?

Answer 16

any cell in the body

Question 17

What type of stem cell can only form one type of tissue?

Answer 17

unipotent

Question 18

What can pluripotent stem cells form?

Answer 18

most types of tissues

Question 19

What can multipotent stem cells make?

Answer 19

certain types of tissues

Question 20

What are some examples of totipotent stem cells?

Answer 20

• fertilized egg

- cells from very early embryo (4 days old)

Question 21

Where can pluripotent stem cells be found?

Answer 21

embryo

Question 22

Where can multipotent stem cells be found?

Answer 22

• bone marrow

- amniotic fluid

Question 23

What type of stem cells is found in the skin and the liver?

Answer 23

unipotent

Question 24

What do eukaryotic cells contain that complicate cell division?

Answer 24

• nuclear membrane
• organelles
• multiple chromosomes

Question 25

WHAT IS A COMPLETE ARRAY OF CHROMOSOMES CALLED?

Answer 25

(answer - genome? karyotype?)

Question 26

What is the term for the physical map of a complete array of chromosomes?

Answer 26

karyotype

Question 27

What are 2 chromosomes of the same type called?

Answer 27

homologous

Question 28

What does homologous mean?

Answer 28

contain the same genes

Question 29

When are eukaryotic chromosomes duplicated?

Answer 29

before division

Question 30

What are the 2 kinds of cells in eukaryotes?

Answer 30

somatic and sex cells (gametes)

Question 31

What is the main difference between somatic cells and sex cells?

Answer 31

contain different number of chromosomes

sex cells are haploid while somatic are diploid

Question 32

How many chromosomes are in a human somatic cell?

Answer 32

46

Question 33

If a cell has 36 chromosomes, what is 2N? N?

Answer 33

2N = 36 (diploid number)
N = 18 (haploid number)

Question 34

How many sets of chromosomes are in somatic cells?

Answer 34

23 pairs - 2 sets

Question 35

What does diploid mean?

Answer 35

having 2 sets of chromosomes

Question 36

What are cells called when they only have 1 set of chromosomes?

Answer 36

haploid

Question 37

How many chromosomes are in human sex cells?

Answer 37

23

Question 38

What is the term to describe a cell with 3 sets of chromosomes? 4?

Answer 38

3: triploid
4: tetraploid

Question 39

What is chromatin made of and in what relative quantities?

Answer 39

60% protein

40% DNA

Question 40

What is chromatin?

Answer 40

an uncondensed chromosome

Question 41

What is a duplex chromosome?

Answer 41

double-stranded

Question 42

What does chromatin wrap around to form a nucleosome?

Answer 42

histones (small protein complexes)

Question 43

SUPERCOILING QUESTION

Answer 43

(answer)

Question 44

NUCLEOSOME QUESTION

Answer 44

(answer)

Question 45

What do cells need to do in order to divide?

Answer 45

1) replicate DNA
2) replicate organelles
3) separate the DNA (and organelles)
4) divide the cytoplasm

Question 46

What are chromosomes called before duplication?

Answer 46

single chromatid

Question 47

What are sister chromatids?

Answer 47

2 identical chromosomes (formed by chromosome duplication)

Question 48

WHAT HOLDS TOGETHER TWO SISTER CHROMATIDS?

Answer 48

CENTROMERE? KINETOCHORE?

Question 49

What are the two overall phases of the cell cycle?

Answer 49

interphase and mitotic phase

Question 50

Approximately how long does the cell spend in interphase?

Answer 50

90% of the cell cycle

Question 51

What phase of the cell cycle does the cell spend 10% of the time in?

Answer 51

mitotic phase

Question 52

What part of the cell cycle does the cell spend 50% of its time in?

Answer 52

S stage (synthesis)

Question 53

Which cell cycle stage is most variable?

Answer 53

G1