B1 Flashcards
(29 cards)
Name an advantage of a light microscope
cheap, can be used anywhere
Name an advantage of an electron microscope
better resolution (0.2nm) , better magnification
What’s the equation linking size of real object, magnification and size of image?
Size of real object = size of image / magnification
Where do most reactions take place?
Cytoplasm
What are ribosomes?
Where protein synthesis takes place, making all the proteins needed in the cell
What does chlorophyll do?
Absorbs light for photosynthesis
Describe a eukaryotic cell
cell membrane, cytoplasm, and genetic material enclosed in a nucleus
describe a prokaryotic cell
cytoplasm and cell membrane surrounded by a cell wall. Genetic material forms a DNA loop rather than being in a nucleus, plasmids
Name a adaption of a nerve cell
Long axon - carries impulses
Many dendrites- to make connections
Name an adaption of a muscle cell
Special proteins - slide over each other to make fibres contract
Many mitochondria - for chemical reactions taking place
Name an adaption of a root hair cell
Large surface area - so more water can move into the cell
Large vacuole - speeds up movement of water by osmosis
Many mitochondria - transfer energy needed
Name an adaption of a photosynthetic cell
Many chloroplasts - more chlorophyll
Large permanent vacuole - keeps cell rigid for osmosis and keeps leaf spread out to capture lots of light
Name an adaption of a xylem cell
Dead lignin spirals form a hollow tube that allows water to move
Dead cells keep cell strong and withstand pressure
Name an adaption of a phloem cell
Sieve plates - allow water carrying dissolved food to move up and down
Companion cells keep them alive
What is diffusion?
The spreading out of particles of any substance, resulting in a net movement from an area of high to low concentration, down the concentration gradient
Define isotonic
Where the concentration of solutes in the solution outside and inside the cell are equal
Define hypertonic
Where the concentration of solutes in the solution outside the cell is higher than inside, causing the cell to shrivel
Define hypotonic
Where the concentration of solutes in the solution outside the cell is lower than inside, causing the cell to burst
What is osmosis?
The movement of water from a dilute to concentrated solution through a partially permeable membrane
Osmosis is important to keep plant cells ____
Turgid
What is active transport?
Movement of molecules from a low to high concentration, against a concentration gradient. It requires energy
What does active transport enable in PLANTS?
allows root hair cells to absorb mineral ions required for healthy growth
What does active transport enable in ANIMALS?
Enables sugar molecules used for cell respiration to be absorbed into the gut into the blood where the concentration of sugar is higher
Describe two adaptions of an effective exchange surface
- large surface area
- thin walls
These both increase rate of diffusion as there is a shorter distance
