Exam #4 - Cell Division Flashcards Preview

BSC 2010 - Biology I > Exam #4 - Cell Division > Flashcards

Flashcards in Exam #4 - Cell Division Deck (108):
1

Where do cells come from?

Cell division

2

Do all cells divide?
What are examples of cells that do NOT divide?

Blood cells
Brain cells
Muscle cells

Not all cells divide, but those produced by cell division divide.

3

What are three reasons why cells divide?

1) Growth/development
2) Repair/regeneration
3) Reproduction

4

Bacteria only have ___ chromosome and it's _______.

one.
circular - meaning it has to ends

5

Bacteria have one circular chromosome and it's copied by ____ _________.

DNA replication

6

Bacterial cells divide by _______ _______.

binary fission

7

How many chromosomes do we have?

46

8

How are eukaryotic cells more complicated?

1) Membrane bound organelles
2) multiple chromosomes

9

The ________ and ________ make their own DNA.

mitochondria and chloroplast

10

What about the E.R and Golgi? What will happen to them during cell division?

They will disassemble and disintegrate into many smaller component parts. The cell divides, and then those parts reassemble and make new E.R and Golgi

11

What are the two types of cell division in eukaryotes?

Mitosis and meiosis

12

Mitosis...
________ daughter cells.

identical

13

Meiosis...
The daughter cells have _____ the number of chromosomes as the parental cell.

HALF

14

The number of cells in the parental cell will always be a _____ number.

even

15

If you have 10 chromosomes, then meiosis gives you daughter cells, each of which have _ chromosomes.

5

16

What is the purpose of mitosis? (3)

Growth/repair/regeneration

17

What is the purpose of meiosis?

Reproduction

18

Mitosis occurs in body cells, also called _______ cells.

somatic

19

Mitosis is a tightly regulated series of events, unique to eukaryotes. Therefore, this process is controlled by many _______.

enzymes

20

______ is the result when cell division goes out of control.

cancer

21

Cell division during the __ phase.

M phase

22

The portion of the cycle in-between cell division is called _________.

interphase

23

Interphase accounts for __% of the cell cycle.

90%

24

What are the 3 sub phases of interphase?

S phase, G1 and G2

25

What occurs during S phase?

1) chromosome duplication
2) DNA synthesis

26

What occurs during G1 and G2?

1) growth
2) prep for next stage

27

Gap 1 Is a gap between ____ ______ and ___ ________.

cell division and DNA replication

28

Gap 2 is between ____ _________ and ____ _________.

DNA replication and cell division

29

What does the S stand for in the S phase?

Synthesis, DNA Synthesis

30

G phase means...

Gap phase

31

In G1, we make the commitment to _______.

divide

32

Also in G1, we make the raw _______.

materials

33

In G1, we make the _________ and ________ for DNA synthesis.

nucleotides and enzymes

34

In G2, we make the raw materials for ____ ________.

cell division

35

The nuclear DNA is carefully INSPECTED in both GAP phases? Why?

The DNA is the code to run the cell...if there's a problem with the code...then continuing this process could be detrimental.

36

What are the two parts of the M phase?

1) Mitosis - division of the nucleus
2) Cytokinesis - division of the cytoplasm

37

In adult organisms, only _____ cells divide.

some

38

A cell can EXIT THE CYCLE and exist in a non dividing state, which is called ___.

G0 (G zero)

39

Where ought the cell leave the cycle if it decides to stop dividing?

At the end of G1, after you have grown to a functional size, you stop progressing and leave. You certainly wouldn't go onto S.

40

How frequently cells 'cycle' depends on the cell ______.

type

41

What are three frequencies of mitosis? Provide examples

1) Continuous - skin, GI tract, blood cells
2) Based on need - liver cells
3) Rare/never - neurons (locked in G0)

42

Most cells are in ____.

G0

43

Eukaryotic chromosomes can become ____/____ compact.

more/less

44

Nuclear DNA is wrapped around _______.
This complexed material is known as ________.

protein
chromatin - both DNA and protein together

45

Why do we wrap DNA and protein together?

We need to condense it so it can fit in the nuclease of the cell

46

One human cell contains _ feet of DNA

6

47

DNA + associated proteins =

chromatin

48

Over the course of the cell cycle, the DNA becomes ______.

compact

49

During M phase, the chromatin packs so tightly that the individual chromosomes become ______ _______.

clearly visible

50

A eukaryotic chromosome: ___ DNA molecule *plus* the associated proteins.

one

51

Eukaryotes have ______ DNA molecules

linear

52

In cell division, the spindle grabs hold of a ________ chromosome, and pulls apart the _________.

replicated
chromatids

53

When you pull apart the chromatids, how many chromosomes do you have?

2

54

A replicated chromosome contains two ______ chromatids.

sister

55

Each sister chromatid contains:
___ DNA
The DNA's are ________.
They are joined at the _________.

one
identical
centromere

56

The spindle attaches to the _________.

centromere

57

One chromosome = ___ DNA

one

58

90% of the cell cycle is in _________.

interphase

59

If 90% of the cell cycle is interphase, what does a nucleus usually contain?

Chromatin

60

A _______ is the total genetic information possessed by an organism.

genome

61

To find that total genetic information, where do you have to look?

Look in any cell

62

How many different genes are there?

Around 20,000

63

How does a cell distribute the sister chromatids to the daughter cells?

It uses the cytoskeleton

64

What are the 'steps' of mitosis?

Prophase
Prometaphase
Metaphase
Anaphase
Telophase

65

Prophase:
-chromosomes _______.
-__________ begin moving to opposite ends
-________ beings to form

condense
centrosomes
spindle

66

What has to happen if the microtubules are going to grab hold of the chromosomes?

***The nucleus has to go away***
Specifically, the **nuclear envelope disintegrates**

67

This allows microtubules to grab hold of of the chromosomes by the __________.

centromeres

68

Prometaphase:
-nuclear envelope _________.
-microtubules grab chromosomes by their __________.

disintegrates
centromeres

69

Metaphase:
-chromosomes in the ______

middle

70

Anaphase:
-chromosomes are pulled _______.
-the cell _________.

apart
elongates

71

Telophase:
-____ nuclear envelopes _______.
-chromosomes _________.

two, reform
DECONDENSE so the chromosomes can become chromatin again

72

What is it that pinches the cell in two?

Microfilaments

73

After telophase, we get cytokinesis, which is...?

the division of the cytoplasm

74

There are two types of reproduction between eukaryotes, what are they?

1) sexual reproduction - two parents
2) asexual reproduction - only one parent gives rise to offspring

75

In _______ reproduction, it's mitosis.

asexual

76

Sexual reproduction involves _______.

meiosis

77

Meiosis occurs in the _______.

gonads

78

Meiosis produces _______ ( _____ cells).

gametes, germ cells

79

Meiosis ______ the number of chromosomes.

halves

80

________ restores the original number.

fertilization

81

What advantage can this complexity have?

Genetic variation

82

What's a karyotype?

Seeing all the chromosomes laid out

83

What are homologous chromosomes?

Chromosome pairs that carry the SAME genes

84

Where do homologous chromosomes come from?

One from mom, the other from dad

85

ONE of each pair is inherited from each parent.
SO...each parent gives us ___ copy of a gene.

ONE

86

Each parent gives you one copy of the gene, so you have ___ of each gene.

two

87

***It's the _________ chromosomes that are separated by meiosis.***

homologous

88

The genes on homologous chromosomes are often NOT _________.

identical

89

Any GENE can have multiple VARIATIONS...and we call those variations ________.

alleles

90

What does this mean in chemical terms? What's so different about the different alleles if they're the same gene?

**They have slight differences in their nucleotide sequence**

91

DO NOT confuse homologous chromosomes with sister chromatids !!!!!!
Which term refers to identical DNA's?
Which ones are present throughout the mitotic cell cycle?

Sister chromatids - IDENTICAL
Homologous chromosomes

92

Where do the homologous chromosomes come from?

Mom and dad! Present throughout the cell cycle

93

How many sex chromosomes do we have?

2

94

That means we have 44 ________.

autosomes - all the non-sex chromosomes

95

Males have an _ and an _ chromosome.

X and an X

XX

96

Females have an _ and a _ chromosome.

X and a Y,

XY

97

X and Y are not _________, which means they must have different ______.

homologous, genes

98

Somatic cells have ___ sets of chromosomes.
-i.e: the homologous pairs!
-one maternal, one paternal
-Somatic cells are _n, or _______.

2n, diploid

99

Gamets have ___ set.
-they are _, or ________.

one
haploid

100

Meiosis separates ....?

homologous chromosomes!!

101

In humans: **n= one set from one parent**
n = __ chromosomes
2n = __ chromosomes

n = 23 (22 autosomes + 1 sex chromosome)
2n = 46 (44 autosomes + 2 sex chromosomes

102

A zygote has __ chromosomes.

46

103

Meiosis has ___ consecutive rounds of cell division (I and II)
Meiosis reduces chromosome # by _____.

two
half

104

Steps of meiosis...

Every single cell division is preceded by ___ ________.
Meiosis I occurs, which separates...?
Meiosis II occurs, which separates...?

DNA replication
the homologous chromosomes
the sister chromatids

105

Meiosis _ Is what makes meiosis unique. It's nothing like mitosis.

Meiosis I

106

Meiosis _ IS mitosis.

Meiosis II IS mitosis.
**You're separating separating sister chromatids**

107

**Which one takes you from diploid to haploid?**

Meiosis I !!!!!!!!!! Diploid to haploid, BOOM

108

Homologous chromosomes are physically BROKEN and REJOINED in _________ _. What is this called?

Prophase I, crossing over