Cell biology Flashcards
characteristics of eukaryotic cell
nucleus is present.
All membrane bound organelles are present
DNA is enclosed in the nucleus
They are multicellular
DNA is linear
Ribosomes are big
They are big cells
Example: Plants and Animals
characteristics of a prokaryotic cell
Nucleus is absent.
Membrane bound organelles are absent.
DNA lies naked in the cytoplasm.
They are mostly unicellular
DNA Is circular
Ribosomes are small
They are small cells.
Example: Bacterial Cell
How is DNA stored in prokaryotic cell?
In circular rings called plasmids, and in the cytoplasm
How to calculate magnification?
image size /actual size = maginfication
I/A =M
Function of the nucleus
It is the brain of the cell
It controls the activities of the cells
It contains DNA which holds our genetic information.
Function of ribosomes
to make amino acids for the cells functions
Which part of the cell labelled above:
(i) traps light for photosynthesis
chloroplast
which part of the cell is made from cellulose
cell wall of plant cell
Give one difference between the structure of the bacterial cell and an animal
cell.
Differences between, the DNA,
Bacteria cells - single stranded, in plasmids
Animal cells- linear DNA contained in the nucleus
Function of a cell membrane
controls what goes in an out of the cell
Function of cytoplasm
Liquid substances where chemical substances take pLace
contains enzymes
that speed up the rate of reaction
Purpose of a permanent vacuole
Contains cell sap
Helps the cell stay firm
Found in the cytoplasm
what are cell walls made out of?
cell walls are made out of cellulose
chloropasts
where photosynthesis takes place
contains chlorophyll where the pigment that traps light
Definition of hypotonic
solution where there is low concentration of salt but high levels of water, the cell will gain water through osmosis and gain mass
def of hypertonic
solution of high salt concentration but low water concentration, in these solution there is less water outside the cell then inside. Water in the inside will leave the cell to a low concentration and lose mass
def of isotonic
equal concentration of salt and water
what is diffusion?
movement of particles from a higher to a lower concentration
what 3 main factors affect the rate of diffusion?
concentration gradient, the temperature, the hotter means more diffusion,surface area
how are unicellular organisms adapted for diffusion?
Large surface area to volume ratio, maximises the area of diffusion
formula for surface area to volume ratio
- find surface area
Number of sides x length x width - find volume
l x w x h - surface area : volume
factors of gas exchange
large surface area, thin membrane, good blood supply,
def of osmosis
movement of water through a partially permable membrane
what is meant by a solution is isotonic to the cell?
the water and salt concentration both inside and outside the cell are the same
what is meant when a solution is hypertonic to a cell?
the salt solution outside the cell is higher then inside the cell
what is meant when a solution is hypotonic to a cell?
salt solution outside the cell is of a lower concentrate then inside the cell
how do plant leaves and stems remain rigid?
through turgor pressure, the water coming in by osmosis causes the vacuole to swell so then the cytoplasam is pushed up against the cell wall
definition of active transport
when the concentration wants to go against the concentration gradient which requires energy usually ATP energy
how is active transport used in diffusion?
active transport is used when glucose is moved from a low concentration in the gut to a high concentration in the blood to then be used for respiration
