S4 - Biology Test (3) Flashcards
What is the process which produces more cells called?
mitosis
What does mitosis do for the body?
Provides new cells for growth and repair of damaged tissues and the replacement of dead or damaged cells
What does mitosis do as well as producing new cells?
It maintains the diploid chromosome complex and compliment
What are haploid cells?
Cells which have a single set of chromosomes
What are diploid cells?
Cells with 2 matching sets of chromosomes
What cells are diploid?
All of them with the exception of gametes
What are gametes?
sex cells, sperm and eggs
What are the stages of mitosis?
- Chromosomes are long and thin, they start to shorten and thicken and they replicate
- Chromosomes, which are now made up of 2 identical chromatids become visible
- Chromosomes line up at the equator and spindle fibres form
- The chromatids are pulled apart by the spindle fibres and the chromosomes move to opposite ends of the cell
- Nuclear membrane reforms and the cytoplasm starts to split
- Cell splits in 2, 2 new identical cells are made
What do stem cells do in animal cells?
They are involved in the growth and repair of tissues
What does ‘unspecialised cells’ mean and what is an example?
- They have the potential to become different types of cells
- stem cells
Where can stem cells be extracted from?
embryos at a very early stage
What are multicellular organisms?
Organisms which have more than one cell type are made up of tissues and organs
Specialisation of cells leads to…
the formation of a variety of cells, tissues and organs
what is a system?
groups of organs working together
what are cells?
the basic unit of life
what are tissues?
groups of specialised cells that work together to preform the same function
what are organs?
groups of tissue which work together
what are systems?
groups of organs which work together
what is the function of red blood cells?
to transport O2 around the body efficiently in the form of oxyhemoglobin
what is the structure of red blood cells?
- has no nucleus
- is biconcave in shape which increases surface area
- contains haemoglobin