B1 Flashcards
How do u calculate magnification?
Magnification =magnification of eyepiece lens x magnification of objective lenses
How do you find the image size of an object ?
Imagine size = actual size x magnification
Resolution?
Resolution is the ability to distinguish between to separate points
What do light microscopes magnify up to
X2000
What do electron microscopes magnify up to ?
X2 000 000
What are plasmids in a prokaryotic cell?
Plasmids are little circular rings of dna
What does the flagella do in a prokaryotic cell
Helps the cell move around and is a long protein strand
What is the use of slime capsules around a prokaryotic cell
Protects the cell
What is the difference between a prokaryotic and a eukaryotic cell?
A eukaryotic cell has a nucleus and a prokaryotic cell doesn’t
Name 3 specialised animal cells
Nerve cell , muscle cells, sperm cells
What are the adaptations of a sperm cell?
-a long tail whips side to side to help the sperm move
-middle section is filled with mitochondria which transfers energy needed first the tail to work
-acrosome stores digestive enzymes for breaking the outer layers of the egg
-a large nucleus contains dna for it to be passed on
What are adaptations for the nerve cell?
-Lots of dendrites to connect with other cell
-long axon that carries the nerve impulse from a place to another
-the synapses pass the impulses to another cell or between a nerve cell and a muscle cell in the body using special transmitter chemicals
-contain lots of mitochondria to provide energy needed to make the transmitter chemicals
What are the properties of a nerve cell?
Nucleus,cell body,axon,dendrites,myelin sheath,synapse
What are the properties of a sperm cell?
Acrosome,tail,middle section,nucleus
What are the adaptations for muscle cells?
-contain special proteins that slide over each other making the fibres contract
-contains lots of mitochondria to help the chemical reactions that takes place as the cells contract and relax
-can store glycogen
What are the adaptations for root hair cells?
-They greatly increase the surface area for water to move into the cell
-that have a large permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cells
-has lots of mitochondria that transfers energy for the active transport of mineral ions into the root hair cells
Name 4 specialised plant cells
Root hair cells, photosynthetic cells, xylem cells,phloem cells
What are the adaptations of photosynthetic cells ?
-contain chloroplast which contains chlorophyll that trap the light needed for photosynthesis
-usually positioned in continuous layers so they can absorb as much light as possible
-have a large permanent vacuole that helps keep the cell rigid
What are the adaptations for xylem cells?
- after the cells die from lignin they form long hollow tubs that allow water and mineral ions to move easily through them
-the spirals and rings of lignin make the cells very strong it helps withstand the pressure of water moving it also helps support the plant stem
What are the adaptations of phloem cells?
- the cell walls between the cells break down to form special sleeve plates this allows water carrying dissolved food to move freely up and down the tubes to where it is needed
-phloem cells are supported by companion cells that help keep the cell alive and the mitochondria of the companion cells transfer the energy needed to move dissolved food around
What does isotonic mean?
A solution that is the same concentration
What does hyper tonic mean ?
A solution that has a higher concentration of
What does hypotonic mean?
A solution that has a lower concentration
What happens when a plant cell is placed in hypertonic solution than the cells contents?
It becomes plasmolysed (shrinks)
What is the function of a nucleus?
Controls the activities of the cell and contains the genetic material (DNA)
What is the function of the cytoplasm?
Where chemical reactions take place
What is the function of a cell membrane?
What controls what substances come into and out of the cell
What is the function of the mitochondria?
Where aerobic respiration takes place
What is the function of ribosomes?
Where protein synthesis takes place (where proteins are made)
What are 3 differences between an animal and plant cell?
Chloroplast,cell wall,vacuole
What is the function of a cell wall in a plant cell?
What strengthens the cell and gives support (made of cellulose)
What is the function of a vacuole?
A space in the cytoplasm which is filled with cell sap
What is the function of chloroplasts?
-they contain green pigment called chlorophyll
-chlorophyll absorbs light so the plant can make food (glucose)
-photosynthesis takes place
What is diffusion?
Diffusion is the net movement of particles from an area of high concentration to an area of low concentration until they are equilibrium (evenly spread out)
What is osmosis?
Osmosis is the diffusion of water molecules through a partially permeable membrane from a dilute solution (which has a high concentration of water) to a concentrated solution (which has a low concentration of water)
What factors affect diffusion?
Temperature,surface area to volume ratio,concentration
How does temperature affect the rate of diffusion?
The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly.
What is active transport?
The net movement of particles from an area of low concentration to an area of higher concentration using energy against the concentration gradient.
