KA1- Producing New Cells Flashcards
What is mitosis
Cell division
Process of a diploid cell dividing
What carries out mitosis
Stem cells
Why is mitosis important
Provides new cells for growth
Repairs damaged tissues
Repairs damaged or dead cells
Maintains the diploid chromosome complement which is important so no information is lost and the cells can carry out the same function as the parent cell
For growth
What controls mitosis
The nucleus
What happens in mitosis
2 identical daughter cells are produced which contain the same number of chromosomes as the parent cell
Why do cells need to divide
To produce new cells for growth and repair of damaged cells
Stage 1 of mitosis
Chromosomes become visible
Each chromosome made up of 2 identical chromatids joined by centrometre
Stage 2 of mitosis
Chromosomes line up at equator of cells and attach to spindle fibers by their centrometres
Stage 3 of mitosis
Spindle fibers contract
Chromatids pulled apart to opposite side of the cell
Stage 4 of mitosis
Nuclear membrane reforms and cytoplasm divided between new cells
Two identical daughter cells, each containing the same number of chromosomes as the original cells are formed
What is a chromosome complement
The number of chromosomes a cell contains
What is the structure of a chromosome
2 identical chromatids joined by a centrometre
Diploid
2 sets of chromosomes
What are stem cells in animals
Unspecialised cells
What can stem cells in animals do
Divide by mitosis in order to self renew which keeps their population relatively constant
Become different types of cells
What are stem cells in animals involved in
Growth and repair
What are the two types of stem cells
Embryonic and tissue
Where are embryonic stem cells derived from
Embryos that develop from eggs that have been fertilised in a laboratory
What are embryonic stem cells capable of
Developing into all cell types
Where are tissue stem cells found
Among other differentiated cells in a tissue or organ
Many tissues such as the bone marrow, brain skeletal muscle, blood vessels, skin, liver, teeth and the heart
What are tissue stem cells capable of
Becoming cells of that tissue
Regenerating surrounding cells damaged by disease or injury etc
What is specialisation of cells
Groups of organs work together to form systems
Hierarchy exists: cells —) tissues —) organs —) systems —) organism
Examples:
Muscle cell —) muscle tissue —) heart —) circulatory system —) the circulatory system makes up part of the human body
Root hair cell —) root tissue —) root —) vascular bundles make up transport system —) transport system makes up part of plant
What does the specialisation of cells lead to
The formation of a variety of cells, tissues and organs
Specialised animal cell examples
Nerve cell: axon allows transmission of electrical nerve impulses
Red blood cells: carry oxygen to body tissue, contain haemoglobin, no nucleus
Sperm cells: male sex cells, have a tail to swim to egg cell
Specialised plant cell examples
Root hour cell: large surface area to allow absorption of water and minerals
Guard cell: control gas exchange charging shape by opening and closing stomata
Palisade cell: chloroplasts present and primary site of photosynthesis in leaf
