Cell Biology Flashcards
Features of animal and plant cell
Eukaryotic
- cell membrane
- cytoplams
- nucleus containing DNA
Bacterial cells
prokaryotic + much smaller
- cell wall
- cell membrane
- cytoplasm
- singular circular strand of DNA and plasmids
Describe: Nucelus
ANIMAL + PLANT
- contains DNA
- enclsed in a nuclear membrane
Describe: cytoplasm
ANIMAL, PLANT + BACTERIA
- liquid substance in which chemical reactions occur
- contains enzymes
- contains organelles
Describe: cell membrane
ANIMAL, PLANT + BACTERIA
- controls what enters and leaves the cell
Describe: mitochondria
PLANT + ANIMAL
- where aerobic respiration occurs - providing energy for the cell
Describe: ribosomes
PLANT + ANIMAL
- where protein synthesis occurs
- found on rough endoplasmic reticulatedeticulum
Describe: chloroplasts
PLANT
- where photosynthesis happens
- contains chrolophyll pigment
Describe: permanent vacuole
PLANT
- contains cell sap
- found within the cytoplasm
- improves cell rigidity
Describe: cell wall
PLANT + BACTERIA
PLANT
- made from cellulose
- provides strength to the cell
BACTERIA
- made of peptidoglycan
Describe: bacterial DNA
- singular strand which floats in cytoplasm
Describe: plasmids
BACTERIA
- small rinds of DNA
How do specialised cells come about?
cell differentiation
- process which involves he cell gaining new sub-cellular structures in order for it to be suited to it’s role
- some cells can differentiate initially or have the ability to keep differentiating (stem cells)
- in animals most cells can only differentiate once, but in plant cells more can
3 types of specialised cells in animals
- sperm cells
- nerve cells
- muscle cells
Sperm cells
specialised to carry male’s DNA to the ovum
- streamlined head and long tail
- many mitochondria supply energy
- acrosome (top of head) contains digestive enzymes which break down outer layer of ova
nerve cells
specialised to transmit electrical signals quickly from one place in the body to another
- long axon, allows impulses to be carried along long distances
- lots of dendrites - extensions from the cell body- brances connections between other nerve cells
- nerve endings have many mitochondria - provide energy to make neurotransmitters (transmitter chemicals) - allow impulses to be passed from one cell to another
muscle cells
specialised to contract eg, move bones, or squeeze eg, smooth muscle (found in blood vessels so blood pressure can be varied) MOVEMENT
- myosin and actin slide over each other causing contraction
- lots of mitochondria
- can store glycogen that’s used in respiration
3 specialised cells in plants
- root hair cells
- Xylem
- Phloem
root hair cells
specialised to take up water by osmosis and mineral ions by active transport - found in the tips of the roots
- large surface area
- large permanent vacuole affects the speed of movement of water from soil to cell
- mitochondria provide energy for active transport
Xylem
transport water and mineral ions from roots to shoots
- lignin causes the cells to die, they become hollow and are joined end to end to produce a tube
- lignin is deposited in spirals which helps the cells withstand pressure
Phloem
carry products of photosynthsis to all parts of the plant
- cell walls of each cell form structures called sieve plates when they break down, allowing the movement of substances from cell to cell
- despite losing many sub-cellular structures, the evergy these cells need to be alive is supplied by the mitochondria of the companion cells
How does cell specialisation come about for stem cells?
genes switched on and off to produce different proteins
