Chapter 1 Flashcards
light microscope
magnification
resolution
m = x2000 r = 200nm
electron microscope
magnification
resolution
m = x 2000000 r = 0.2nm
equation
magnification
size of real object
size of image
magnification = size of image / size of real object
components in an animal cell (5)
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
Explain:
nucleus
controls all activities of a cell and contains genes
Explain:
cytoplasm
where most chemical reactions take place
Explain:
cell membrane
controls the passage of substances into the cell
Explain:
mitochondria
where aerobic respiration takes place
Explain:
ribosomes
where protein synthesis takes place
components in a plant cell (8)
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, chloroplasts, cell wall, permanent vacuole
Explain:
cell wall
Strengthens the cell and gives it support
Explain:
chloroplasts
It contains chlorophyll which absorbs light and can make food by photosynthesis
Explain:
permanent vacuole
Keeps the cell rigid to support the plant
Give 3 examples of eukaryotic cells.
plants, fungi, protists
Give an example of a prokaryotic cell.
bacteria
Basic structure of a bacteria (6)
cell membrane, slime capsule, cell wall, plasmids, flagella, cytoplasm
What do all eukaryotic cells contain (3)
cell membrane, cytoplasm, genetic material enclosed in a nucleus
What do prokaryotic cells contain (4)
cytoplasm, cell membrane, cell wall, the genetic material is not in a distinct nucleus but in small loops called plasmids
what is differentiation
As an organism develops, cells differentiate to form different types of specialised cells. It allows the cell to carry out a certain function.
What is the purpose of a nerve cell
to carry electrical impulses around the body of an animal
How is a nerve cell specialised (3)
1) Lots of dendrites to make connections to other nerve cells
2) An axon that carries the nerve impulse from one place to another. They can be very long
3) The nerve endings or synapses are adapted to pass the impulses to another cell or between a nerve cell using special transmitter chemicals. They contain lots of mitochondria to provide the energy needed to make the transmitter chemicals.
What is the purpose of a muscle cell
to contract and relax
How is a muscle cell specialised (3)
1) They contain special proteins that side over each other making the fibres contract
2) They contain many mitochondria to transfer the energy needed for the chemical reactions to take place
3) They can store glycogen, a chemical that can be broken down and used in cellular respiration
What is the purpose of a sperm cell
They contain genetic material from the male parent and have to swim to and break the egg.
How is a sperm cell specialised (4)
1) A long tail helps the cell swim
2) They are full of mitochondria which provides energy
3) The digestive enzymes can be used for breaking down the outer layers of the egg
4) a large nucleus for the genetic information to be passed on
What is the purpose of a root hair cell
The root hair cells help them to take up water and mineral ions more efficiently .
How is a root hair cell specialised (3)
1) They greatly increase the surface area available for water to move into the cell
2) They have a large permanent vacuole that speeds up the movement of water by osmosis from the soil across the root hair cell.
3) They have many mitochondria that transfer the energy needed for the active transport of mineral ions into the root hair cells.
what is the purpose of photosynthetic cells
This is a cell where photosynthesis occurs
How is a photosynthetic cell adapted (3)
1) They contain specialised green structures called chloroplasts that trap the light needed for photosynthesis
2) They are usually positioned in continuous layers in the leaves and outer layers of the stem of a plant to absorb as much light as possible
3) They have a large permanent vacuole that helps keep the cell rigid and helps support the plant. They also keep the leaf spread out to increase SA.
what is the purpose of the xylem cell
This is the transport tissue in plants that carries water and mineral ions from the roots to the highest leaves and roots.
How is the xylem cell adapted (2)
1) These cells are alive when they are first formed but a special chemical called lignin builds up in spirals in the cell walls. The cells die and form long hollow tubes that allow water and mineral ions to move easily through them, from one end of the plant to the other.
2) The spirals and rings of lignin in the xylem cells make them very strong and help them withstand the pressure of water moving up the plant. They also help support the plant stem.
what is the purpose of the phloem cell
It is a specialised transport tissue that carries the food made by photosynthesis around the body of the plant. The dissolved food can move up and down the phloem tubes to where it is needed.
How is the phloem cell adapted (2)
1) The cell walls between the cells break down to form special sieve plates. These allows water carrying dissolved food to move freely up and down the tubes to where it is needed.
2) Phloem cells lose a lot of their internal structures but they are supported by companion cells that help to keep them alive. The mitochondria of the companion cells transfer the energy needed to move dissolved food up and down the plant in phloem.
explain: diffusion
the spreading out of the particles which results in the net movement from an area of high concentration to an area of low concentration.
what affects the rate of diffusion
the rate of diffusion is affected by: 1) the difference in concentrations
2) the temperature
3) the available surface area
explain: osmosis
the movement of water from a dilute to a more concentrated solute solution through a partially permeable membrane that allows water to pass through.
explain: turgor
the pressure that builds up until no more water can enter the cell
explain: active transport
moves substances from a dilute solution to a more concentrated solution (against a concentration gradient)
What does active transport require
uses energy released from food in respiration
What does active transport allow plants and animals to do (2)
1) allows plant root hairs to absorb mineral ions required for healthy growth from dilute solutions in the ground.
2) enables sugar molecules used for cell respiration to be absorbed from lower concentration in the gut into the blood where the concentration of sugar is high
