Exam #4 - Cell Division Flashcards
(108 cards)
1
Q
Where do cells come from?
A
Cell division
2
Q
Do all cells divide?
What are examples of cells that do NOT divide?
A
Blood cells
Brain cells
Muscle cells
Not all cells divide, but those produced by cell division divide.
3
Q
What are three reasons why cells divide?
A
1) Growth/development
2) Repair/regeneration
3) Reproduction
4
Q
Bacteria only have ___ chromosome and it’s _______.
A
one.
circular - meaning it has to ends
5
Q
Bacteria have one circular chromosome and it’s copied by ____ _________.
A
DNA replication
6
Q
Bacterial cells divide by _______ _______.
A
binary fission
7
Q
How many chromosomes do we have?
A
46
8
Q
How are eukaryotic cells more complicated?
A
1) Membrane bound organelles
2) multiple chromosomes
9
Q
The ________ and ________ make their own DNA.
A
mitochondria and chloroplast
10
Q
What about the E.R and Golgi? What will happen to them during cell division?
A
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
Q
What are the two types of cell division in eukaryotes?
A
Mitosis and meiosis
12
Q
Mitosis…
________ daughter cells.
A
identical
13
Q
Meiosis…
The daughter cells have _____ the number of chromosomes as the parental cell.
A
HALF
14
Q
The number of cells in the parental cell will always be a _____ number.
A
even
15
Q
If you have 10 chromosomes, then meiosis gives you daughter cells, each of which have _ chromosomes.
A
5
16
Q
What is the purpose of mitosis? (3)
A
Growth/repair/regeneration
17
Q
What is the purpose of meiosis?
A
Reproduction
18
Q
Mitosis occurs in body cells, also called _______ cells.
A
somatic
19
Q
Mitosis is a tightly regulated series of events, unique to eukaryotes. Therefore, this process is controlled by many _______.
A
enzymes
20
Q
______ is the result when cell division goes out of control.
A
cancer
21
Q
Cell division during the __ phase.
A
M phase
22
Q
The portion of the cycle in-between cell division is called _________.
A
interphase
23
Q
Interphase accounts for __% of the cell cycle.
A
90%
24
Q
What are the 3 sub phases of interphase?
A
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
