Chapter 12 and 13 Flashcards
1
Q
Where do cells come from?
A
Cells come from other cells by cell division
2
Q
Give examples of cell that do not divide
A
Cells in adult bodies such as blood, brain cells (neurons and spinal cells) and muscle cells
3
Q
Why do cells divide?
A
- Growth/ development
- Repair/ regeneration
- Reproduction
4
Q
What is the only reason that single-cell organisms divide?
A
Reproduction
5
Q
What is the life of a cell?
A
Cell division, becoming larger, then dividing again
6
Q
Do all cells divide?
A
No, not all cells divide but all cells are produced through cell division
7
Q
Prokaryotes (bacteria) divide by what method, and how long will that method continue?
A
Binary Fission
It will continue as long as there is adequate nutrients
8
Q
Prokaryotes (bacteria) have what type of chromosomes?
A
A singular circular chromosomes with no ends; a covalently closed circle
9
Q
What do prokaryotic cells do to ensure that each daughter cell receives a copy of the chromosome?
A
The chromosome is anchored to the cell membrane to ensure that each daughter cell recieves a copy
10
Q
State the two reasions why is eukaryotic cell division more complicated than prokaryotic division
A
Euk. cell division is more complicated because
- membrane bound organelles
- mitochondria, chloroplasts
- endoplasmic reticulum (ER) , golgi
- multiple chromosomes
11
Q
What happens to the ER and the Golgi during reproduction?
A
ER and golgi are disassembled during reproduction and re-assembled after the division is complete
12
Q
How many chromosomes due human cells have?
A
46 chromosomes
13
Q
What are the two types of cell division in eukaryotes?
A
Mitosis and Meiosis are the two cell divisions in eukaryotes
14
Q
What is lost in cell division?
A
Mass is lost in cell division
15
Q
Which cell division produces two daughter cells identical to the parent?
A
Mitosis produces two identical daughter cells
16
Q
Which cell division produces daughter cells with 1/2 of the number of chromosomes?
A
Meiosis produces daughter cells with 1/2 of the number of chromosomes
17
Q
Mitosis is performed for what functions?
A
Growth
Repair/ Regeneration
18
Q
Meiosis is performed exclusively for what purpose?
A
Reproduction (ex. sperm, eggs )
19
Q
Mitosis occurs in what type of body cells?
A
Somatic cells
20
Q
What is a tightly regulated series of events, unique to eukaryotes?
A
Mitosis
21
Q
Sperm, eggs and stems cell that produce eggs do not do which cell division?
A
Sperm, eggs and stems cell that produce eggs do not do mitosis
22
Q
10% of Cell division occurs during which phase?
A
The M phase
23
Q
Mitosis is controlled by what?
A
Catalytic enzymes control mitosis
24
Q
The cell cycle is the most intensely studied field. Why?
A
Cancer
Uncontrolled cell reproduction
25
90% of the cell cycle between cell division is in which phase?
Interphase
| 90% of the cycle between cell division is interphase
26
What are the three sub-phases of interphase?
The S phase and the 2 gap phases, G1 and G2
27
What happens during S phase?
Chromosome duplication and DNA synthesis
28
What separates the M and S phase?
The G1 and G2 phases
29
What happens during the G1 phase?
Growth/ prep for the S phase occurs in the G1 phase
30
What happens during the G2 phase?
more growth/ prep for the S phase
31
Mitosis occurs at which part of the cell cycle?
the end of the cell cycle
32
What are the two parts of the M phase?
Mitosis and cytokinesis
33
What is ctyokinesis?
division of the cytoplasm
34
What happens to nuclear DNA during both Gap phases and why?
Nuclear DNA is inspected to prevent mutations during replication
35
What is the phase where a cell leaves the cell cycle and enters a non-dividing state?
G0 ( G zero) phase
36
Where is a good exit for entering G0?
During G1 after mitosis ( M phase)
37
KEY CONCEPT: During the cell cycle, the genetic material become _____/_______ compact based on need.
MORE/LESS
| During the cell cycle, the genetic material becomes more/less compact based on need
38
The frequency of mitosis is dependent on what?
Cell type
| The frequency of mitosis is dependent on cell type.
39
On the basis of cell type, how frequent does mitosis occur?
1. Continuous
- skin cells
- integumentary system
- GI tract
2. Based on need
- Liver cells
3. Rare/never
- neurons in the adult body
A cell will perform mitosis continuously, on a need basis or rarely/ never.
40
The G0 phase applies to which two frequency of mitosis?
Based on need
Rare/ never
The G0 phase applies to cell that perform mitosis on the basis of need or rarely/ never perform mitosis.
41
Most human cells are in which G phase?
G0 phase
| Most human cells are in the G0 phase
42
During cell cycle, how does the genetic material or nuclear DNA become more compact?
The nuclear DNA wraps around proteins called histones to become more compact
43
Chromatin is a complex composed of what?
DNA and proteins
| Chromatin is a complex of DNA and Protein
44
One human cell contains how much DNA
~6ft
| One human cell contains approximately 6 ft.
45
Does chromatin become more or less condensed as it goes through the M phase? Why?
The chromatin becomes more compact so that it can be easily manipulated during cell reproduction
(EX.when spindles grab the DNA)
46
KEY CONCEPT: During M phase, the DNA is _____ ________
Tightly packed
47
When is DNA is clearly visible and why?
DNA is only clearly visible during cell division ( M phase) because they are tightly packed
48
One DNA molecule plus the associated proteins is what?
Eukaryotic chromosome
49
In terms of shape, eukaryotic chromosomes have what type of DNA?
One lone, LINEAR DNA
| Eukaryotic chromosomes have one long, linear DNA
50
An eukaroytic chromosome can contain how many genes?
100's -1000's
| An eukaryotic chromosome can contain 100's - 1000's of genes
51
KEY CONCEPT: Each euk species has a specific number of chromosomes, how many chromosomes do human cells have?
46 chromosomes
52
DNA is replicated in which phase?
S phase
| DNA is replicated in S phase
53
A REPLICATED chromosome has how many DNA in M phase?
2 DNA
| A REPLICATED chromosome has 2 DNA during M phase.
54
A replicated chromosome contains how many sister chromatids?
2 sister chromatids
| A replicated chromosome has two sister chromatids
55
Each chromatid (from a replicated chromosome) contains how many DNA molecules?
```
1 DNA molecule
Each chromatid (from a replicated chromosome) contains one DNA molecule
```
56
The DNA from two sister chromatids are _______
Identical
| The DNA from two sister chromatids are identical
57
Before splitting, the sister chromosomes are held together where?
Centromere
| Before splitting, the sister chromosomes are held together at the centromere
58
After cell division, the chromatids "disappear". What happened to them?
The chromatids de-condense and are no longer visible
59
What is the total genetic information possessed by an organism?
Genome
| A genome is the total genetic material possessed by an organism
60
Where can the genome be found?
In every cell of the organism
| The genome can be found in every cell of the organism
61
The human cell consists of how many genes?
~25,000 genes
62
How does a cell distribute the sister chromatids to daughter cells?
by re-purposing the cyctoskeleton
| A cell will re-purpose the cyctoskeleton to distribute the sister chromatids to daughter cells
63
Where do microtubules come from?
The centrosome
| Microtubules come from the centrosome
64
What are the step of mitosis (ppmat)?
```
Prophase
Prometaphase
Metaphase
Anaphase
Telophase
```
65
What happens in the first stage of mitosis?
Prophase ("pro"-before)
- chromosomes condense for manipulation
- centrosomes splits into 2 and begin moving to opposite ends
- spindle beings to form
66
True or false, Mitosis is a dynamic and continuous process
True
| Mitosis is dynamic and continuous process
67
What happens in the second stage of mitosis?
Prometaphase ("prometa" - before metaphase)
- nuclear envelope dissinegrates, goes away
- microtubles grab chromosomes by the centromeres and pull
68
What happens in the third phase of mitosis?
Metaphase ("meta" -middle)
| - the chromosomes line up in the middle
69
What happens in the fourth phase of mitosis?
Anaphase ("ana" - apart)
- chromosomes are pulled apart towards poles
- cell elongate
70
What happens in the fifth and last stage of mitosis?
Telophase ("telo" -end )
- the two nuclear envelopes reform from the pieces of the previous envelope
- chromatid de-condense, unravel into chromatins
71
What pinches the cell into two?
Microfilaments
| Microfilaments form a contracting ring that pulls the membrane with it and pinches the cell in two
72
What is cytokinesis?
Division of the cytoplasm
73
What are the two types of reproduction in eukaryotic cells?
Asexual and sexual reproduction
74
What is asexual reproduction?
Asexual
- a single parent required to produce offspring
- offspring identical to parent
- by mitosis
75
What is sexual reproduction?
Sexual
- two parents required to produce offspring
- offspring vary from parents and each other
- involves meiosis
76
Meiosis occurs only where?
The gonads
| Meiosis only occurs in the gonads, ( ovaries in females and testes in males)
77
Meiosis produces what vs. somatic cells?
Gametes, "germs" (vs. somatic cells)
78
Meiosis will produce how many chromosomes?
1/2 the number of chromosomes
| Meiosis will produce half the number of chromosomes
79
If meiosis produces only half the number of chromosomes, how is the original number of chromosomes restored?
Fertilization
| Fertilization restores the original number by putting together two gametes ( ie. an egg and sperm)
80
What is the advantage (genetically) of having two parents?
Diverse DNA and variation
81
What is a karyotype?
A chromosome laid out
82
By looking at karotypes, what are the three things that can be observed about chromosomes?
- There are different sizes
- Centromere positions vary
- They stain differently
83
What are the three things that should be noted about a human karotype?
- the number of chromosomes (46)
- that all the chromosomes are replicated (found because extracted from dividing cell)
- the chromosomes are paired
84
SUPER MAJOR KEY CONCEPT: What are homologous chromosomes?
Chromosome pairs that carry the same genes
85
SUPER MAJOR KEY CONCEPT: Where do homologous pairs come from?
One chromosome from each pair is inherited from each parent
86
SUPER MAJOR KEY CONCEPT: In homologous chromosomes, each parent gives how
many copies of each gene?
One
| Each parent gives one copy of the gene
87
SUPER MAJOR KEY CONCEPT: The genes MAY NOT be _________
identical
| The genes in homologous pairs MAY NOT be identical
88
Between sister chromatids and homologous pairs, which are present through out the cell cycle (G phase, M phase and S phase) and which are identical?
Homologous pairs are present throughout the cell cycle and the chromatids are identical
89
What are the multiple variations in genes?
Alleles
90
In chemical terms, what does if alleles are variations in genes?
Chemically speaking, the variations in alleles means they have slightly different sequences of nucleotides
91
KEY CONCEPT: What are autosomes?
All chromosomes NOT directly involved in determining sex
92
KEY CONCEPT: What are sex chromosomes?
Chromosomes that determine sex
93
KEY CONCEPT: How many autosomes and how many sex chromosomes do humans have?
44 autosomes and 2 sex chromosomes
94
KEY CONCEPT: X and Y chromosomes are NOT ________ which means they carry different genes
X and Y chromosomes are NOT homologous which means they carry different genes
95
KEY CONCEPT: Males have which two chromosomes?
X and Y
96
KEY CONCEPT: Females have which two chromosomes?
X and X
97
Somatic cells are what type of ploid?
Diploids
| Somatic cells are diploids
98
How many sets of chromosomes does a diploid have and where do the chromosomes come from?
Two sets of chromosomes and one from the mother and one from the father
99
In the set 2n, n represents what?
The number of chromosomes in one set
100
Gametes are what type of ploids?
diploids
101
How can the number of chromosomes in a somatic cell be presented with n?
2n since there are 2 sets
102
Gametes have how many sets or n's?
1 set, one n
103
n is how much in humans? how much is 2n?
```
n = 23 (22 autosomes + 1 sex chromosomes)
2n= 46 ( 44 autosomes + 2 sex chromosomes)
```
104
Meiosis has how many consecutive rounds of cell division?
Two (I and II)
105
Meiosis reduces the number of chromosomes by how much?
1/2
106
What are the steps of meiosis?
1. Preceded by DNA replication
2. Meiosis I separates the homologous chromosomes
3. Meiosis II separates the sister chromatids
107
Which phase of Meiosis takes you from diploid to haploid?
Meiosis I
108
KEY CONCEPT: Meiosis I separates what?
The homologous chromosomes
109
KEY CONCEPT: Meiosis pair, align and separate chromosomes in which phases?
- PAIR in prophase I
- ALIGN in metaphase I
- SEPARATE in anaphase I
110
KEY CONCEPT: How many mechanisms generate variation from ONE generation to the NEXT?
Three
111
What is independent assortment?
The chromosomes in gametes are a random mix of maternal and paternal chromosomes
112
What is crossing over?
When homologous chromosomes are physically broken and rejoined
113
What leads to chromosomes with new combinations of alleles?
crossing over
114
What is random fertilization
When any sperm may fertilize any ova
115
Which of the three mechanism for generating variation occur in meiosis?
Independent assortment and crossing over
