What is a somatic cell?
Any body cell that is not involved in reproduction.
How do somatic cells divide?
By mitosis.
What does mitosis produce?
Two genetically identical diploid daughter cells.
Why is mitosis important in somatic cells?
It maintains the diploid chromosome number for growth and repair.
What is a germline cell?
Gametes and the germline stem cells that divide to form gametes.
How do germline stem cells divide to maintain the germline population?
By mitosis.
How do germline stem cells produce gametes?
By meiosis.
What does meiosis produce?
Four genetically different haploid gametes.
What happens in the first division of meiosis?
Homologous chromosomes are separated.
What happens in the second division of meiosis?
Chromatids are separated.
What is the chromosome number of diploid cells?
23 pairs of homologous chromosomes.
What is the chromosome number of haploid gametes?
23 single chromosomes.
What is cellular differentiation?
The process where a cell expresses certain genes to produce proteins that give it specialised functions.
What are embryonic stem cells?
Pluripotent cells from the early embryo that can differentiate into all cell types.
Why are embryonic stem cells pluripotent?
All their genes can be switched on.
What are tissue (adult) stem cells?
Multipotent cells involved in the growth
Why are tissue stem cells multipotent?
They can differentiate into a limited range of cell types within one tissue.
Where are blood stem cells found?
In the bone marrow.
What can blood stem cells differentiate into?
Red blood cells, platelets, phagocytes and lymphocytes.
What are therapeutic uses of stem cells?
Repairing damaged or diseased tissues or organs.
Give SQA examples of therapeutic stem cell use.
Corneal repair and regeneration of damaged skin.
What are research uses of stem cells?
Studying disease development, cell growth, differentiation, gene regulation and drug testing.
Why are embryonic stem cells ethically controversial?
Their use involves the destruction of embryos.
What causes cancer cells to form?
They divide excessively because they do not respond to regulatory signals.
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Unit 1-Division And Differentiation In Human Cells26
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Unit 1-Structure And Replication Of DNA33
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Unit 1-Gene Expression30
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Unit 1-Mutations30
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Unit 1-Human Genomics10
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Unit 1-Metabolic Pathways30
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Unit 1-Cellular Respiration34
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Unit 1-Energy Systems In Muscle Cells24
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Unit 2-Gamete Production And Fertilisation32
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Unit 2-Hormonal Control of Reproduction23
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Unit 2-The Biology Of Controlling Fertility24
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Unit 2-Antenatal And Postnatal Screening62
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Unit 2-The Structure And Function of Arteries, Capillaries And Veins31
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Unit 2-The Structure And Function Of The Heart58
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Unit 2-Pathology Of Cardiovascular Disease (CVD)38
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Unit 2-Blood Glucose Levels And Obesity35
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Unit 3-Divisions Of The Nervous System And Neural Pathways31
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Unit 3-The Cerebral Cortex7
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Unit 3-Memory25
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Unit 3-The Cells Of The Nervous System And Neurotransmitters At Synapses31
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Unit 3-Non-Specific Body Defences27
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Unit 3-Specific Cellular Defences Against Pathogens34
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Unit 3-Immunisation16
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Unit 3-Clinical Trials Of Vaccines And Drugs11
