2.1.6 Cell Division Flashcards
what is the function of a guard cell?
to open and close the stomata
what are the adaptations of guard cells?
- pores
—> enables gas exchange -
thin outer walls and thick inner walls
—> force guard cells to bend outwards, opening stomata
what is the function of root hair cells?
absorb water and mineral ions from the soil
what are the adaptations of root hair cells?
- large SA
—> more water absorbed -
permeable cell wall
—> entry of water and ions - extra mitochondria
—> provide energy for active transport
what is the function of palisade cells?
do most of photosynthesis
what are the adaptations of palisade cells?
- many chloroplasts
—> so a lot of sunlight is absorbed - thin walls
—> faster rate of diffusion for co2
what is the function of erythrocytes?
carries oxygen in the blood
what are the adaptations of erythrocytes?
- biconcave disk shape
—> provides large SA for gas exchange - no nucleus
—> more room for more haemoglobin
what is the function of a neutrophil?
defends body against diseases
what are the adaptations of neutrophils?
- flexible
—> allows engulfing of pathogens - many lysosomes
—> digestive enzymes to break down pathogens
what are the adaptations of sperm cells?
- flagellum
—> to swim - lots of mitochondria
—> energy provided to swim - acrosome
—> contains digestive enzymes which enables egg penetration
which processes must occur in a cell during interphase before mitosis can take place?
- protein synthesis
- dna replication
- centrioles replication
- synthesis of organelles
what are two ways cell division in plants differs from cell division in animals ?
- no centrioles in plant
- cell wall forms in plant
where are two parts in a plant where meristematic tissue can be found
- tip of root
- tip of shoot
what is G1 in interphase?
- growth of cells
- growth of organelles
- protein synthesis
what’s G2 phase?
- growth of cells
- growth of organelles
- protein synthesis
- spindle begins to form
what is the S phase?
- DNA replication
- full copy of DNA
what does the G0 checkpoint do?
cell leaves cycle either permanently or temporarily because:
- it has fully differentiated
- DNA repairing
what happens at G1 checkpoint?
cell checks if chemicals needed for DNA replication are present and checks if DNA is damaged before entering S
what happens at G2 checkpoint?
- checks for a mutation in the DNA
- daughter cells might not receive identical genetic information
- proteins might not function
why does mitosis occur?
- asexual reproduction
- repair of damaged tissues
- growth of an organism
what happens in prophase?
- nuclear envelope breaks down
- chromosomes condense
- centrioles move to opposite ends of the cell forming a spindle fibre
what happens in metaphase?
- spindle fibres attach to centromeres on chromosome
- chromosomes line up along the equator of the cell
what happens in anaphase?
- centromeres divide, separating each pairs of sister chromatids
- spindle contracts, pulling chromatids to opposite ends of the cell
