Cells-bio mocks revision
cell membrane function
only allows certain substances in and out the cell
Ribosomes function
where protein synthesis takes place
Mitochondria function
where oxygen is used and energy is released in aerobic respiration
Nucleus
Controls the cell and contains DNA to make more
Cytoplasm function
where most chemical reactions take place
Cell wall function
strenthens cell and provides support
permanent vacuole function
filled with cell sap to keep cell rigid and support the plant
Chloroplast function
contains chlorophyll which absobs light for photosynthesis
what sub-cellular structures are in plant cells but not animal
cell wall, permanent vacuole and chloroplast
magnification equation
size of image=magnification x size of object
magnification of both types of microscope
light= x2000
electron= x2,000,000
How do you prepare a slide
collect a sample of the cells and put them on a clean slide, then carefully place a slip over the sample
how do you view a slide with a microscope
put the slide on the stage anduse the coarse focus adjustment until the cells come into view. Then use the fine focus adjustment until the image is clear. This can be done with any 3 of the objective lenses for different magnification.
examples of eukaryotic cells
Animal, plant, fungi, protista
example of prokaryotic cell
bacteria
difference between eukaryotic and prokaryotic cells (3points)
eukaryotic are bigger and have a nucleus. prokaryotic are single cell organisms
purpose of flagella
a 'tail' used to move around
purpose of slime capsule
stores waste and stops drying
purpose of plasmids
carries code for very specific feature
How do prokaryotes store DNA
a DNA loop
how do eukaryotes store DNA
a nucleus
what are specialised cells
they have adaptions and structures that enable them to carry out a particular function
what are stem cells
unspeciqalised cells that can divide and develop into any type of specialised cell
what is diffusion
the random movement of a substance from an area of high concentration to an area of low concentration
factors that affect diffusion rate (4points)
1. temperature
2. surface area
3. concentration gradient
4. particle size
define osmosis
the movement of water from a silute solution to a concentrated solution through a semi-permiable membrane
define dilute solution
high water low solute
deine concentrated solution
low water, high solute
how does water move in and out of cells
Osmosis
Isotonic solution
the concentration of solutes is the same as the inside of the cell
Hypertonic solution
the concentration of solutes is higher than inside the cell
hypotonic solution
the concentration of solutes is lower than inside the cell
what happens to a plant cell in a hypotonic solution
it is under turgor pressure becuase water enters the cell via osmosis
what happens to a plant cell in an isotonic solution
the cell is flaccid because water flows in and out the cell freely
what happens to a plant cell in a hypertonic solution
the cell is plasmolyzed because all the water leaves the cell via osmosis
define active transport
moves substances from an area of low concentration to an area of high concentration using a carrier protein.
where is the energy for active transport supplied from
respiration
what is active transport used for in plants
to take in mineral ions from the soil through the roots
what is active transport used for in animals
when the glucose concentration in the intestine is lower than in the intestinal cells, active transport is used to move glucose
surface area : volume ratio of small/large organisms
small organisms have large ratio and large organisms have small ratio
ideal exchange surfaces
. large surface area
. short diffusion distance
. sufficient blood supply (in animals, to maintain a steep concentration gradient)