B1- Cell structure and transport Flashcards
Conversion from cm to nanometres
1cm= 1millim
1millim= 1000 micrometres
1 micrometre= 100 nanometres
1 nanometres (1 X 10^-7m)
Light microscope benefits:
- can magnify x200
- can view live specimen
- quite cheap
- easy to store
Electron microscope:
- can magnify x2 000 000
- must be stored under certain temp and pH
- can give 3d images
Animal cell structures:
Plant cell structures:
nucleus: controls cell activities
cytoplasm: chemical reactions take place
ribosomes: protein synthesis
cell membrane: controls passage of substances in and out cell
mitochondria: respiration
chloroplasts: photosynthesis
cell wall: made of cellulose strength
vacuole: support cell and keep it rigid
Eukaryotic cells:
- plant and animal cells
- cell membrane and a cytoplasm and DNA is contained to a nucleus
Prokaryotic cells:
- bacteria
- cell membrane and cytoplasm but DNA not contained to a nucleus
- forms dna loop called plasmids
Sperm cell function and specialisation:
-swim through water to the egg cells and break through the outer layer of the egg
- tail to help swim
- middle section with lots of mitochondria for respiration
- acrosome contains digestive enzymes needed to break the egg
- large nucleus which contains genetic info needed to be passed on
Nerve cell adaptions:
dendrites at the top which help make connections to other nerve cells
- long axon (body) to help it carry the impulse
- synapse contains lots of mitochondria which provide energy needed to make transmitter chemicals
Muscle cell adaptions:
- need to contract and relax
- special proteins which slide over each other
- lots of mitochondria which transfer energy needed to contract and relax
- contain glycogen which can be broken down into glucose for respiration
Root hair cells adaptions:
- increase in SA which allow more water to move into cell
- large vacuole which speeds up the rate of osmosis
- lots of mitochondria which transfer energy for active transport
Xylem cells:
- transport tissue which carry water and mineral ions around the plant
- dead cells which form hollow tubes which allow water and mineral ions to flow through them
- reinforced by spiralled lignin which make it strong and help it withstand the pressure of water
Phloem cells:
- transport food made from photosynthesis to the different plant cells
- cell wall breaks down to form sieve plates which allow water carrying dissolved foods to move through them
What is diffusion?
net movement of particles in a solution or gas from an areas of high concentration to an area of low concentration
What affects the rate of diffusion?
- temperature
- concentration gradient
- SA to Volume ratio
What osmosis?
net movement of a solvent (water) through a partially permeable membrane from an area of high water concentration to an area of low water concentration
What does concentrated and dilute mean?
concentrated- high concentration of solutes and low water concentration
dilute- low concentration of solutes and high concentration of water
What does:
isotonic
hypertonic
hypotonic mean?
isotonic- concentration of the solutes are the same
hypertonic- concentration of solutes higher outside (low water concentration)
-water leaves cell
hypotonic- concentration of solutes lower outside (high water concentration)
-water enters cell
Why is osmosis needed in animals?
- osmosis balances water in the cytoplasm
- can cause big problems as water can enter cells and cause them to burst
Why do plants need osmosis?
- plants rely on osmosis to support the leaves
- water moves into plants and causes vacuole to swell up and press against the cytoplasm
- pressure build up until no more water can enter
- known as turgor pressure
What do plants need the outside solution to always be?
hypotonic
What is the term when water enters the plant?
plasmolysis
What is active transport?
the movement of solutes from an area of low concentration to an area of high concentration
(against the concentration gradient)
How do dissolved substances move?
-diffusion and active transport
Where does the energy needed for active transport come from?
energy is needed to carry molecules across a membrane then to the original position- from respiration
Where is active transport used in animals and plants?
- plants: root hair cells
- animal: cells lining gut- glucose absorbed out of gut into kidney tubules- glucose needed for respiration
