b1 - cell structure and transport Flashcards
what is the equation for magnification?
magnification = image size / real size
what is resolution?
the ability to clearly distinguish the individual parts of an object
what is the resolving power of a microscope?
measure of how well you can distinguish between 2 points
what are the structures in an animal cell?
nucleus
cytoplasm
cell membrane
mitochondria
ribosomes
what is the function of the nucleus?
controls all activities of the cell
contains the genes
what is the function of the cytoplasm?
a liquid gel where most chemical reactions take place
what is the function of the cell membrane?
regulates what enters and leaves the cell
protects and supports the cell
what is the function of the mitochondria?
where aerobic respiration occurs (releases energy for the cell)
what is the function of the ribosomes?
where protein synthesis takes occurs
what structures do plant cells have that animal cells don’t?
chloroplasts
cell wall
permanent vacuole
what is the function of the cell wall?
made of cellulose, supports + strengthens the cell
what is the function of the chloroplasts?
contain chlorophyll which absorbs light for photosynthesis
what is the function of the permanent vacuole?
filled with cell sap to help keep the cell turgid
what is a eukaryotic cell?
a cell that has a nucleus and organelles
give examples of eukaryotic cells
plants
animals
fungi
protists
what is a prokaryotic cell?
a cell without a nucleus
they are single felled living organisms
give examples of prokaryotic cells
bacteria
archaea
what structure does the dna in eukaryotic cells form?
chromosomes
what structure does the dna in prokaryotic cells form?
plasmids (small rings of dna found in the cytoplasm)
what is a flagella?
long, thin whip-like structure that helps organisms move through moist or wet surroundings
what is differentiation?
the process by which a cell changes to become specialised for its job
give examples of specialised cells
red blood cells
nerve cells
gamete cells
root hair cell
muscle cells
xylem + phloem cells
photosynthetic cells
how are nerve cells specialised?
lots of dendrites to connect to other cells
a long axon carrying the nerve impulses
synapses at the ends to pass messages on
lots of mitochondria to provide enough energy
how are (striated) muscle cells specialised?
contain special proteins that slide over eachother making the fibres contract
lots of mitochondria to release energy needed for contraction
term-51
store glycogen to be broken down + used in cellular respiration
how are egg cells specialised?
large diameter for them to carry enough stored food
contain stored food needed for early stages of development
large, haploid nucleus contains genetic info
how are sperm cells specialised?
long tail + streamlined head to help swim faster
lots of mitochondria to release energy
enzymes stored in the acrosome to digest through the egg
large nucleus containing genetic info
how is a root hair cell specialised?
increased surface area for water to move into cell
large permanent vacuole to speed up movement of water by osmosis from soil across root hair cell
lots of mitochondria to transfer energy needed for active transport of mineral ions into root hair cell
how are red blood cells specialised?
large surface area that allows absorption of oxygen
biconcave shape creates the large surface area for absorption of oxygen
able to fold to travel through the capillaries
small diameter allowing them to pass through small blood vessels
how are palisade mesophyll cells specialised?
contain chlorophyll that absorbs light needed for photosynthesis
usually positioned in continuous layers of leaves + outer layers of stem to absorb max amount of light
large permanent vacuole to keep cell rigid as a result of osmosis
how are xylem cells specialised?
hollow in the centre
have very few sub-cellular structures so that water + mineral ions can easily flow through them
spirals and rings of lignin to make them strong + help withstand pressure of water moving up plant
how are phloem cells specialised?
end walls allow sugars through but support the tubes
arranged end to end into tubes
have companion cells in between them
what is diffusion?
the net movement of particles of gas or any substance in solution from an area of high concentration to an area of low concentration down the concentration gradient
what is net movement?
the overall movement of particles
what factors affect rate of diffusion?
temperature
surface area
difference in concentration
pressure
what substances use diffusion?
gases eg oxygen, co2
glucose
waste products eg urea
what is gas exchange?
the process by which oxygen is transported to cells and carbon dioxide is transported from cells
