Cell Biology Flashcards
features of eukaryotic cells
cell membrane
cytoplasm
nucleus containing dna
features of prokaryotic cells
smaller
cell wall
cell membrane
cytoplasm
single circular strand of DNA and plasmids
function of nucleus
contains dna coding for a particular protein needed to build cells
enclosed in a nuclear membrane
function of cytoplasm
liquid substance in which chemical reactions occur
contains enzymes
organelles are found in it
role of cell membrane
controls what enters and exits the cell
role of mitochondria
where aerobic respiration reactions occur, providing energy for the cell
role of ribosomes
where protein synthesis occurs
function of chloroplasts
where photosynthesis takes place, providing food for the plant
contains chlorophyll pigment which harvests the light needed for photosynthesis
function of permanent vacuole
contains cell sap
found within the cytoplasm
improves cells rigidity
function of cell wall
made from cellulose
provides strength to the cell
difference of cell wall in bacterial cells
made of a different compound
where are single circular strands of dna found in bacterial cells
float un the cytoplasm as have no nucleus
what are plasmids in bacterial cells
small rings of dna
what is differentiation?
a process that involves the cell gaining new sub cellular structures in order for it to be suited to its role
how often can stem cells differentiate
their whole life
how many times can cells differentiate in animals?
once
how many times can cells regenerate in plants?
retain the ability to regenerate whenever
what is the function of a sperm cell?
specialised to carry the males dna to the egg for successful reproduction
what adaptions do sperm cells have?
streamlined head and long tail
many mitochondria for energy for cell to move
acrosome has digestive enzymes which break down the outer layers of membrane of the egg cell
what is the function of nerve cells?
transmit electrical signals quickly from one place in the body to another
what are the adaptions of nerve cells
axon is long so impulses can be carried along long distances
lots of extensions from the cell body called dendrites meaning branches connections can form with other nerve cells
the nerve endings have many mitochondria which supply the nerve to make neurotransmitters
what is the function of muscle cells
specialised too contract quickly to move bones or squeeze therefore causing movement
what adaptations do muscle cells have
special proteins that slide over each other causing the muscle to contract
lots of mitochondria to provide energy from respiration for contraction
store glycogen which is used in respiration
what is the function of a root hair cell
specialised to take up water by osmosis and mineral ions by active transport from the soil
adaptations of root hair cells
large surface area from root hairs for more water to move in
large permanent vacuole affects the speed of movement for water from soil to the cell
mitochondria to provide energy for the active transport of mineral ions to the root hair cell
function of xylem cells
specialised to transport water and mineral ions up the plant from the roots to the shoots
adaptations of xylem cells
lignin causes the cells to die and become hollow to join end to end and form a tube of water for mineral ions to move through
lignin is deposited in spirals which helps the cells withstand the water pressure
what is the function of phloem cells
specialise dto carry the products of photosynthesis to all parts pf the plants
what is the adaptations of phloem cells
cell wall for sieve plates when they break down allowing substances to move from cell to cell
what do bacterial cells have instead of a nucleus?
single circular strand of DNA that floats freely in the cytoplasm
what are plasmids?
small rings of dna in a bacterial cell
magnification calculation
magnification = image size / real size
what do light microscopes do?
use light and lenses to form an image of a specimen and magnify it
what do light microscopes let you see?
individual cells and large sub cellular structures like nuclei
what do electron microscopes do?
use electrons to form an image with a higher magnification than light microscopes
what do electron microscopes let us see?
smaller things like internal structure of mitochondria and chloroplasts, ribosomes and plasmids due to the higher resolution
what is resolution
the ability to distinguish between two points
what is differentiation?
the process by which a cell changes to become specialised for its job
what happens as cells change to help them carry out new functions?
different subcellular structures developed
when does differentiation usually occur?
as an organism develops
when is the ability to differentiate lost in animal cells
early stage
when is the ability for plant cells to differentiate lost
never in most plants
what are the cells that differentiate in mature animals used for?
repairing and replacing cells such as skin and blood cells
what are undifferentiated cells called
stem cells
phloem and xylem cells adaptations
form tubes which transports food and water around plants
xylem cells hollow and phloem cells few subcellular structures for flow of movement
how do stem cells turn into different types of cell
divide to produce more undifferentiated cells
can differentiate from here depending on instructions given