cells reproduce by duplicating their contents and then splitting into two daughter cells
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what are the cell cycle checkpoints
there are two main checkpoints the G1/ S phase also called the restriction points and the G2/M. There are one halfway through mitosis and one in early G1
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what is the purpose of these checkpoints
to prevent uncontrolled division that would lead to tumours, to detect and repair damage to DNA
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what are the stages of interphase and what happens during this phase
M phase - a checkpoint chemical triggers condensation of chromatin and cell growth stops
G0 - a resting phase during early G1, cells may undergo apoptosis or differentiation or some stay indefinitely
G1 - ensures the cell is ready to enter S phase, cells
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what is the significance of mitosis in the life cycle
asexual reproduction - single-celled protoctists such as Amoeba and paramecium divide by mitosis
Growth - all multicellular organisms grow by producing more cells that are genetically identical to each other and parents
tissue repair - heal wounds
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what are the stages of mitosis and occur during these stages
prophase - chromosomes have replicated, nuclear envelope breaks down centromeres divide, spindle fibre form
metaphase - chromatids attach to spindle at equator and attach to centromeres
anaphase - centromeres split motor p pull chromatids to oppo ends
t
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what is cytokinesis and where does this happen in the cell cycle
it happens once mitosis is complete and is where the cell splits into two, so that each new cell contains a nucleus
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what is the significance of meiosis in life cycle
it is used in sexual reproduction and helps to increase genetic variation
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what does meiosis mean
it means reduction and it occurs in diploid germ cells to produce haploids gametes
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what is the difference between mitosis and meiosis
in mitosis there is only one division whilst in meiosis there are two divisions and four stages to each and at the end cytokinesis may occur
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what is the homologous chromosome
matching chromosomes, containing the smae genes at he same places (loci). They may contain different alleles for some of the genes
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what are the main stages of meiosis and what occurs in these stages
first division is the same as mitosis and the second division is the same.
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how does meiosis produce genetic variation
crossing over during prophase 1 shuffles alleles, independent assortment of chromosomes in anaphase 1 leads to random distribution and also independent assortment in anaphase 2 leads to further distribution and haploid gametes are produce, which can unde
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why do cells need to specialise
multicellular organisms are larger and therefore have smaller SA:Vol ration, which means they need specialised cells to carry out particular functions
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what does differentiation mean
it is a process by which stem cells become specialised into different types of cell to help it carry out particular functions
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What are some examples of specialised animal cell and what are their specializations
erythrocytes carry more oxygen from the lungs to respiring cells
neutrophils - ingest invading pathogens
spermatozoa - many mitochondria for aerobic respiration, enzymes to digest the egg
epithelial cells - are flattened in shape
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What are some examples of specialised plant cells and what are their specializations
palisade cells - they are long and cylindrical , contain many chloroplast for photosynthesis
guard cells light energy to produce ATP O2 produced during photosynthesis diffuses out the stomata
root hair cells - hair like projections increase SA special c
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What the four main animal tissues and what are the structures and functions of each
epithelial, connective tissues, muscle tissue, and nervous tissue
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What the three main plant tissues and what are the structures and functions of each
epidermal tissue, vascular tissue and meristematic tissue
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what is an organ
collection of tissues working together to perform a function or related functions
unspecialised cells able to express all of its genes and divide by mitosis
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what are some sources of stem cells
embryonic stem cells, stem cell in the umbilical cord, adult stem cells (found in infants and children) and pluripotent stem cells developed in laboratories
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how are stem cells used in medicine an research
bone-marrow transplants, drug research and developmental biology
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how have stem cell been used to repair damaged tissues or replace tissues
stem cells can be used to treat mice, bone marrow stem cells can be developed into liver cells, stem cells directed to become nerve tissue could be used to treat Alzheimer's or Parkinson's, or could be eventually used to treat arthritis, strokes, burns, v
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functions of plant organs
leaf - photosynthesis
root - absorption of mineral ions and anchorage in soil
stem - support, holds leaves up, transportation of water and mineral ions
flower - sexual reproduction
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what is ensured because the cell cycle happens in a specific sequence
the cycle cannot be reversed, and the DNA is only duplicated once during each cell cycle
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Other cards in this set
Card 2
Front
what are the cell cycle checkpoints
Back
there are two main checkpoints the G1/ S phase also called the restriction points and the G2/M. There are one halfway through mitosis and one in early G1
Card 3
Front
what is the purpose of these checkpoints
Back
Card 4
Front
what are the stages of interphase and what happens during this phase
Back
Card 5
Front
what is the significance of mitosis in the life cycle
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