specialised cells Flashcards
sperm cell adaptations
- Only contain half the genetic material of a normal cell
- flagellum, which allows them to swim to the ovum
- lot’s of mitochondria which provide energy from respiration for swimming
- they are streamlined to make swimming easier
what is a zygote
a fertilised egg cell
what is differentiation
the process by which a cell changes to become specialised
job of a nerve cell
to send electrical impulses around the body
adaptions of the nerve cell
myelin insulates the axon and speeds up the transmission of nerve impulses
synapses on the end of axon * junctions which allow the impulse to pass from one nerve cell to another
dendrites - * increase the surface area so that other nerve cells can connect more easily
adaptions of the muscle cells
muscle cells can contract “they contain protein fibres which can change their length
full of mitochondria to provide energy for muscle contraction
work together to form muscle tissue
adaptions of root hair cell
hairs increase the surface area of the root so it can absorb water and dissolved minerals more effectively
do not contain chloroplasts - * no light underground so no photosynthesis - no need for chloroplasts
where are xylem found?
what is their function?
in stem
they carry water and dissolved minerals from roots to leaves
xylem cells adaptions
thick walls containing lignin * providing support to plant
end walls have broken down - * cells now from a long tube so water and dissolved minerals can flow more easily
no internal structures e.g nucleus * easier for water and minerals to flow
what are phloem cells?
phloem tubes carry dissolved sugars up and down the plant
phloem cells adaptions
phloem vessel cells have no nucleus aND SIEVE PLATES * allows dissolved sugars to move through the cells interior
each phloem vessel cell has a companion cell connected by pores - mitochondria
provides energy to phloem vessel cell
What can adult bone marrow stem cells be used for
They can form many types of cells including blood cells.
Treatment with stem cells may be able to help conditions such as diabetes and paralysis
What is therapeutic cloning ?
When an embryo is produced with the same genes as the parent. Stem cells from the embryo will not be rejected by the patients body so they may be used for medical treatment.
What is the use of meristem cells in plants
Stem cells can be used to produce clones of plants - rare species can be cloned to protect them from extinction
Disease resistant crops can be cloned to produce large numbers of plants for farmers.
