1
Q
cell continuity
A
all cell develop from preexisting cells - to do this living cells need to divide
2
Q
nucleus surrounded by
A
a double membrane
3
Q
nuclear pores
A
allow for controlled entry and exit of molecules in and out of the nucleus
4
Q
nucleolus
A
area in nucleus which stains darkly - where ribosomes are made
5
Q
chromosomes
A
collided strands of DNA and proteins that becomes visible in the nucleus at cell division
6
Q
location of chromosomes
A
nucleus
7
Q
chromosomes composed of:
A
protein/DNA
8
Q
genes
A
code for the production of a specific protein (giving you a certain characteristic)
9
Q
amount of chromosomes in a typical human cell
A
46
10
Q
male sex chromosomes (letters)
A
XY
11
Q
female sex chromosomes letters
A
XX
12
Q
somatic cells
A
normal cells. not associated with the reproductive system (46 chromosomes)
13
Q
gamete
A
sex cells
14
Q
female gamete
A
egg
15
Q
male gamete
A
sperm
16
Q
gametes amount of chromosomes
A
23
17
Q
chromatin
A
name given to chromosomes when they are not dividing
18
Q
cell cycle
A
describes the life cycle of the cell including when the cell is dividing and not dividing
19
Q
cell cycle is dividing into 3 stages
A
interphase, nuclear division(mitosis and meiosis)
20
Q
interphase
A
the phase in the life cycle of a cell when it’s not dividing (longest phase in the cell cycle)
21
Q
events in interphase
A
the cell is getting ready for mitosis , so its is producing identical copies of everything( including organelles such as mitochondria and chloroplast)
22
Q
processes involving DNA
A
Dna replication( this allows the chromosomes to become double -stranded)
Transcription
23
Q
other cellular processes that occur during interphase
A
protein synthesis, photosynthesis, respiration
24
Q
biomolecules formed during interphase
A
carbhydrates, proteins
25
interphase meaning
when cell is not dividing, DNA replication
26
DNA replication
the process of producing two identical copies of DNA from one DNA molecule. a single stranded chromosome makes an exact copy of itself to form a double stranded chromosome. when a chromosome becomes double stranded, mitosis can now occur
27
structure of DNA
DNA is made up of nucleotides, has two strands and these strands are linked by chemicals called bases
28
four bases used in DNA
adenine, thymine, guanine, cytosine
29
complementary base pairs
the bases that correspond with each other
30
AT corresponding pair
Adenine, thymine
31
GC corresponding pair
Guanine, Cytosine
32
shape of DNA
double helix shape
33
what are bases held together by
hydrogen bond
34
mechanism 1 of DNA replication
double helix unwinds
35
mechanism 2 of DNA replication
enzymes breaks down the bonds between bases (DNA helicase)
36
mechanism 3 of DNA replication
DNA nucleotides containing one of the four bases (ATCG) enter from the cytosol and attach to the exposed bases on the old strands. They attach in a way so that complementary base pairs (A with T, G with C) are matched with each other. (Each side of the DNA molecule acts as a template for the new DNA that is formed)
37
mechanism 4 of DNA replication
DNA polymerase joins the nucleotides to the new strand. Each new DNA has half old and half new DNA. Identical to the original DNA strand and to the other new partner strand
38
mechanism 5 of DNA replication
Each new piece of DNA rewinds to forma double helix
39
result of DNA replication
single stranded chromosome becomes a double stranded chromosome. (each of the two strands has identical genetic information)
40
centromere
the point at which the strands are held together
41
sister chromatids
identical chromosome strands
42
haploid cells
one set of chromomsomes, sperm, symbol- n
43
diploid cells
two sets of chromosomes
44
function of haploid cells
allow for sexual reproduction, as they are capable of fusing with each other
45
diploid cells
chromosomes are in pairs in the diploid cell, number =46 (2n)
46
homologous pair
two chromosomes of similar size with the same sequence of genes
47
mitosis
form of nuclear division in which one nucleus divides to form two nuclei, each containing the same number of chromosomes with identical genes (takes place in somatic cells)
48
#cells produced by mitosis
2
49
cells produced by mitosis are...
genetically identical
50
role of mitosis in single celled (unicellular) organisms
method of asexual reproduction (eg yeast and bacteria
51
role of mitosis in in multicellular organisms
growth and repair in cells
52
how does a single celled zygote divide and develop into an embryo
through mitosis
53
4 stages of mitosis
PMAT- prophase, metaphase, anaphase, telophase
54
prophase
At the end of interphase and early prophase chromatin starts to contract. Chromosomes become visible as double stranded structures. Nucleolus dissapears. Spindle fibres appear in cyptoplasm. Nuclear membrane starts to break down.
55
Metaphase
Nuclear membrane is fully broken down. Spindle fibres from each end(pole) of the cell attaches to the centromere. The chromosomes line up across the middle or the equator of the cell.
56
anaphase
The spindle fibres contract. This causes the centromeres to split . One strand (or chromosome) from each double strand chromosomes is pulled to opposite poles of the cell. The 4 chromosomes pulled to each pole have identical genes.
57
Telophase
The chromosomes at each pole elongate and become hard to distinguish(chromatin). The spindle fibres break down. One or more nucleoli begin to reform. A new nuclear membrane forms around the chromatin at each end of the cell.
58
cancer def
A disorder in which certain cells lose their ability to control both the rate of mitosis and the number of times mitosis takes place
59
cause of tumour
abnormal cells can continue to divide and can produce a mass of tissue called a tumour( can be benign or malignant)
60
Benign cancer
Cells stop dividing after some time, not life threatening(doesn't invade other tissues), can be surgically removed eg warts
61
Malignant cancer
Uncontrollable multiplication of abnormal cells, can be life threatening because they invade other cells and move from one place to another, cancer cells continue to divide indefinitly
62
cancer causing genes
oncogenes
63
environmental factor associated with causing cancer
carcinogens
64
causes of cancer
infectious agents, environmental factors, genetic suspectability
65
what is cytokinesis
dividing of the cyptoplasm
66
cell division follows immedialy after..
mitosis
67
cells divide in x to from xy
x=2 y=daughter cells
68
daughter cells contain
same number of identical chromosomes as each other
69
cytokinesis in animal cells
cleavage furrow forms. a cleavage furrow is a shallow grove in the cytoplasm that becomes deeper, until it eventually divides the cytoplasm and the cell splits in two.
70
cytokinesis in plant cells
Cell plate formation. In plants, the rigid cell wall prevents a cleavage furrow from forming. Instead, cell plate forms. Vesicles gather in the area between two nuclei. These vesicles contain the material, mainly cellulose, which forms the new cell walls . Two cell walls form within cell plate(one for each daughter cell)
71
region between two adjacent cell walls
middle lamella
72
infectious agents
viruses and bacteria that cause cancer eg HPV
73
infectious agents trigger cancer by
altering genes that control cell division, suppresing the immune system
74
Envirnomental factors, also known as
carcinogens
75
genetic suspectibilty
some people have genes that make them more likely to get cancer. Risk of cancer increases with age due to the build up of mutations over time
75
carcinogens(environmental factors that cause cancer
smoking cigarettes, exposure to ultraviolet, contact with pesticides
76
factors that increase the risk of cancer but are not controllable
Age (Risk increases with it)
Family history (some cancers are inherited)
Reduced immunity levels (due to infection or drugs)
Exposure to carcinogens (environmental factors)
77
Factors that increase the risk of cancer and are controllable
Smoking cigarettes
Being overweight
Poor diet
Lack of excersise
78
prevention and treatment methods
Early detection
Surgery
Radiation Therapy
Chemotherapy
Vaccinations
Lifestyle changes
79
examples of early detectable signs of cancer on the body
A lump/ swelling, persistent coughs, indigestion
80
what does meiosis produce
gamete cells (23 chromosomes)
81
Meiosis def
Meiosis is a form of nuclear division in which four daughter nuclei contain half the chromosome number of the parent nuclei. The cells resulting from meiosis are not identical
82
Causes of meiosis
Genetic variation, Number of chromosomes of the parent cell to be halfed
83
Meiosis occurs in the...
ovaries and testes
84
role of meiosis
Produces gametes( haploid cells) allowing for sexual reproduction and allows for greater variation within a species
85
Number of daughter nuclei formed by mitosis
2
86
number of chromosomes in daughter nuclei formed by mitosis
same as parent nuclei
87
genetic makeup of daughter nuclei formed by mitosis
genetically identical to parent nucleus and each other
88
Number of daughter nuclei and cells formed by meiosis
4
89
number of chromosomes in daughter nuclei formed by meiosis
half the number of the parent
90
genetic makeup of daughter nuclei formed by meiosis
genetically different from parent and each other (variation)
91
DNA
deoxyribosucleic acid
92
RNA vs DNA
DNA is double stranded but RNA is not
biology
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