23 chromosomes (haploid male sperm) + 23 chromosomes (haploid female egg) = ???
…= fertilisation
46 chromosomes (diploid)
Haploid?
Only one copy of each chromosome
Diploid?
Two copies of each chromosome
What is a zygote?
Fertilised egg cell
What is a cell cycle?
Sequence of growth & division to make new cells
Interphase is what?
Cell growth and DNA replication
What is mitosis?
Cell division
Diploid daughter cells are…?
Genetically identical to each other & the parent cells
What are the mitosis stages?
Prophase Metaphase Anaphase Telophase CYTOKINESIS
Cell differentiation?
A cell becomes specialised to perform a specific function
Mitosis forms two genetically identical daughter cells
.
Growth is caused by…?
Increase in cell number and increase in cell size
Meristem cells
Keeps plant growing
Guard cells ?
Opening & closing to the stomata, minimise water loss
Palisade cells?
Have chloroplasts inside them
Xylem vessels?
Transport water using long xylem tissue and cells
Root hair cells?
Increases surface area with tiny hairs on the roots, can absorb more water this way.
Stem cells - types?
Embryonic - animals
Adult - “
Meristem - plants
Advantages of stem cells ?
Used in medicine
Disadvantages of stem cells?
Cancer and rejection
Embryonic stem cells
- only found in embryos
- they can specialise to form any cell (totipotent)
Adult stem cells
- not just found in adults
- means hey are only able to form a few cell types (pluripotent/multi potent)
- found in foetuses and in born organisms too
Meristem stem cells
- Source of stem cells in plants
- stem means they can make other cells not that they are in the stem of a plant
- found in tips of the shoot and the root
Benefits of stem cells
Long bones -
- bone marrow makes blood cells. Bone marrow cells are adult stem cells and so deities and specialise to form just blood cells
