1 Cells, tissues and organs Flashcards
What cells belong to both plants and animals and which ones only belong to plant cells?
Animal and Plant:
- nucleus
- cell membrane
- cytoplasm
- ribosomes
- mitochondria
Plant only:
- cell wall
- vacuole (permanent)
- chloroplasts
What does the nucleus do?
contains DNA and controls the cell
What does the cell membrane do?
controls what substances enter and exit the cell
What does cytoplasm do?
liquid gel where chemical processes take place for life
What do ribosomes do?
where protein synthesis takes place providing protein for the cell
what do mitochondria do?
in cytoplasm where oxygen is used and most energy is released during respiration
What does the cell wall do?
made of cellulose which supports and strengthens the cell
What does the vacuole (permanent) do?
filled with cell sap and glucose (carbohydrate) to be used as energy
What does a bacterial cell consist of?
- cytoplasm and a membrane surrounded by a cell wall
- gene’s aren’t in a distinct nucleus but free in cytoplasm
- also plasmids containing extra genetic material and flagella are attached allowing the cell to move
How big is a bacterial cell compared to a yeast cell?
They are smaller than yeast cells
How are bacteria used when they aren’t harmful?
- to make food such as yogurt and cheese
- in sewage treatment
- to make medicines
What does a yeast cell consist of?
- a single celled organism
- contain a nucleus, cytoplasm and membrane
- surrounded by a cell wall
How are yeast specially adapted to survive and how do they reproduce?
- they reproduce through asexual budding involving a new yeast cell growing out of the original cell to form a new separate yeast organism
- are specialised to survive for a long time, even in a lack of oxygen - they can use anaerobic respiration
What is anaerobic respiration?
When sugar is broken down in the absence of oxygen, producing ethanol and carbon dioxide
Otherwise known as fermentation
Where is fermentation used?
- to make bread
- to make alcohol
What are the 3 main adaptations of fat cells?
body stores fat in fat cells which helps us survive when food is in short supply
- have a small amount of cytoplasm and large amounts of fat
- have few mitochondria because the cell needs very little energy
- can expand - up to 1000 x its original size as it fills up with fat
What are the 3 main adaptations of cone cells (from human eye)?
(light sensitive layer of the eye-retina-making it possible to see in colour)
- outer segment contains a special chemical-visual pigment-which changes chemically in coloured light and needs a lot of energy to change back into its original form
- middle segment is packed full of mitochondria which release the energy needed to reform the visual pigment, allowing you to see continually in colour
- final part is a specialised synapse that connects to your optic nerve - when coloured light makes your visual pigment change, an impulse is triggered which crosses the synapse and travels along the optic nerve to your brain
What are the 2 main adaptations of root hair cells?
(grow close to the tips of growing roots, need to take in lots of water and dissolved mineral ions efficiently-always closest to the xylem tissue which carries water and mineral ions up into the rest of the plant)
- root hairs increase the surface area of water to move into the cell
- have a large permanent vacuole that speeds up the movement of the water by osmosis from the soil across the root hair cell
What are the 4 main adaptations of sperm cells?
(usually released a long way from the egg they are going to fertilise, contain genetic information from the male parent and depending on the type of animal have to move through water or the female reproductive system to reach and break into the egg)
- long tail whips from side to side helping sperm move towards the egg
- middle section is full of mitochondria which provide energy for the tail to work
- acrosome at the head stores digestive enzymes for breaking down the outer layers of the egg
- large nucleus contains genetic information to be passed on
How do you work out net movement?
number of particles moving in - number of particles moving out
How do dissolved substances such as oxygen move in and out of cells?
Diffusion
What is diffusion?
the net movement of particles from an area where they are at a high concentration to an area where they are at a lower concentration
What is the concentration gradient?
the greater the difference in concentration, the faster the rate of diffusion
How does temperature affect the rate of diffusion?
an increase in temperature means the particles in a gas or solution move more quickly
diffusion takes place more rapidly as the random movement of particles speeds up
