PM - plasma membrane - controls what goes in/out cell
GA - golgi apparatus - modifies proteins
State 5 differences between plant and animal cells
1. Cell wall - only in plant cells, not in animal cells
2. Chloroplasts - only in plant cells, not in animal cells
3. Polysaccharides - starch used as storage compound in plant cells and glycogen is storage compound in animal cells
4. Vacuole - large and fluid filled in plant cells, not usually present in animal cells
5. Shape - fixed shaped in plant cells - usually regular. Able to change shape in animal cells - usually rounded
Look at the diagram below.
State what happens in interphase
G1 The cell performs its normal differentiated function. Protein synthesis/ mitochondria replication/ chloroplast replication.
S DNA replication. At this point the mass of DNA in the cell has doubled.
G2 Preparation for cell division
State 8 differences between prokaryotes and eukaryotes
Prokaryotes are less than 5um, eukaryotes are more than 10um
Prokaryotes are always unicellular, eukaryotes are often multi-cellular
Prokaryotes have no nucleus but have a naked loop of DNA (nucleoid) eukaryotes have a membrane bound nucleus with linear chromosomes bound with histones
Prokaryotes have no membrane bound organelleseukaryotes have membrane bound organellesProkaryotes have small ribosomes (70S) eukaryotes have large ribosomes (80S)
Prokaryotes have no mitochondria eukaryotes have mitochondria
Prokaryotes have cell division by binary fission eukaryotes have cell division by mitosis/meiosis
Prokaryotes' reproduction is mainly asexual, eukaryotes' reproduction is asexual or sexual
What does differentiation mean?
When cells become different cell types to perform different jobs.
Examine the diagram and label
List some functions of membrane proteins
Hormone binding sites
Channels for passive transport
Pumps for active transport.
What is diffusion?
Diffusion is the passive movement of particles from a region of high concentration to a region of low concentration.
What is osmosis?
Osmosis is the passive movement of water molecules, across a partially permeable membrane, from a region of lower solute concentration to a region of higher solute concentration.
What are tumours?
They are the result of uncontrolled cell division and that these can occur in any organ ortissue.
What happens in interphase of cell cycle?
Is an active period in the life of a cell. Many metabolic reactions occur, including protein synthesis, DNA replication and an increase in the number of mitochondria and/or chloroplasts.
Mitosis is used in what processes?
What is facilitated diffusion?
Passive net movement of molecules from regions of high concentration to low concentration, through a selectively permeable membrane, facilitated by carrier proteins.
What is a 'tissue'?
A group of similar cells all performing the same function.
Look at the diagram. What are the pink balls representing? What about the sticks that point inwards?
Pink balls = hydroPHILIC phophate heads
Sticks = hydroPHOBIC lipid tails
What is the prokaryotic cell wall made from?
What is passive transport?
Passive transport involves no expenditure of energy on the part of the cell and includes diffusion, facilitated diffusion and osmosis.
What is active transport?
Active transport requires the expenditure of energy and it includes the sodium–potassium pump, endocytosis, and exocytosis.
Why is the sodium-potassium pump important?
The sodium–potassium pump is extremely important in the human body because it brings about the proper ion levels within nerves and muscles so that they can operate efficiently.
What is endocytosis?
Endocytosis occurs when a portion of the plasma membrane is pinched off to enclose macromolecules or particulates needed by the cell. This results in the formation of a vesicle inside the cell.
What is exocytosis?
Exocytosis is essentially the opposite of endocytosis. The Golgi apparatus is essential to the process of exocytosis.
What is the difference of cytokinesis in plant and animal cells?
Cytokinesis in plant cells occurs with the formation of a cell plate inside the cell and spreading out. Cytokinesis in animal cells occurs with the pinching in of the plasma membrane resulting in a cleavage furrow. It is the presence of the cell wall in plant cells but not in animal cells that brings about this difference in cytokinesis.
Give a therapeutic use of stem cells.
Restoration of insulation tissue in neurons (from May 2012 paper)
What is the approx thickness of the plasma membrane of a cell?
What kind of amino acids do you find on the INSIDE of transmembrane proteins (the channel)?
Polar amino acids
HELP:Polar bears (live on the 'edge' of the planet ...therefore, polar amino acids like to be on the edgeof membranes - either sticking out from cell membranes - or forming channels.
Where donon-polar amino acids form in membranes?
The are the parts of the proteins that cause them to get embeddedinto the membrane
HELP:Polar bears live on the 'edge' of the planet. Non polar bears.....opposite (inside)