B1 Cell Structure And Transport Flashcards
How do you work out magnification?
Image size/size of real object
How far can a light and electrons microscope magnify
Light- x2000
Electron- x2000000
Animal cell structure
Nucleus Cytoplasm Cell membrane Mitochondria Ribosomes
What does the nucleus do
Controls all the activity of the cell. Contains the genes
What does the cytoplasm do?
Where most of the chemical reactions take place
What does the cell membrane do?
Controls what enters and exits the cells of substances such as glucose.
What does the mitochondria do?
Where aerobic respiration takes place. Releases energy for the cell.
What does ribosomes do?
Makes all the protein need in the cell.
What other features are in an algae and plant cell?
Cell wall
What do some plant cells have?
Chloroplast and permanent vacuole which is filled with sap
What do Eukaryotic cells contain?
A cell membrane
Cytoplasm
A nucleus with genetic information in a nucleus
How are prokaryotic cell different to eukaryotic cells?
The genetic is not held in a nucleus in a DNA loop and may contain extra loops of DNA which are called plasmoids
Example of a prokaryotic cell
Bacteria cells
What do Nerve cells have to make it specialised?
Dendrites to make make connections to other nerve cells
An axon that carries the nerve impulse from one place to another
A synapses to pass the impulses to another cell
What do muscle cells have to be specialised?
Contain special proteins that slide over each other to make the fibres contract.
Many mitochondria to transfer the energy for the cells to contract and relax
Can store glycogen that is used to transfer the energy needed for the fibres to contract
What do sperm cells have to be specialised?
A long tale that whips from side to side to help it move
Full of mitochondria to transfer energy for the tail to work
Acrosome stores digestive enzymes to break down the outer layer of the egg
Large nucleus to pass lots of genetic information
What do root hair cells have to be specialised?
Increase surface area for water to move into the cell
Have a large permanent vacuole that speeds up the movement of water by osmosis from the soil
Many mitochondria to transfer the energy needed for the active transport of mineral ions
What do photosynthetic cells have to be specialised?
Contain chloroplasts that trap the light for photosynthesis.
Has a large permanent membrane to keep it rigid due to osmosis
Xylem cell are specialised because..
The spirals and rings make them very strong and help them withstand the pressure of water moving up the plant.
It also supports the plant stem
What is diffusion?
The spreading out of particles of a gas or any substance in a solution from an area of high concentration to low concentration down a concentration gradient
Examples of diffusion
Sharks smelling blood from a far distance
Smelling food from a small distance away
How is the rate of diffusion effected?
The rate of diffusion is affected by the difference in concentrations, the temperature and the available surface area
How can the rate of diffusion be increased?
Having a large surface area
Being thin to provide s short diffusion path
Increasing concentration gradient
Increase in temperature
In a animal cell, water into cell is
Lysis
In a animal cell water out of cell is
Crenation
In a plant cell water in cell is
Turgid
In a plant cell water out of cell is
Plasmolysed
What substances move in and out of cells during diffusion?
Glucose and gases such as carbon dioxide and oxygen
What is osmosis?
osmosis is the movement of water molecules through a partially permeable membrane
What solution does water molecules move from?
A dilute solution to a concentrated solution of less water molecules through a partially permeable membrane
How can animal cells be damaged in osmosis?
If the concentration outside the cell changes dramatically it may burst the animal cell
If the concentration of solutes in the solution outside the cell is the same as the internal concentration the solution is…
Isotonic
If the concentration of solutes in the solution outside the cell is higher than the internal concentration the solution is…
Hypertonic
If the concentration of solutes in the solution outside the cell is lower than the internal concentration the solution is…
Hypertonic
What is active transport?
Active transport is the movement of a substance across a cell membrane of a low concentration to a high concentration against a concentration gradient
What does active transport allow root hair cells to do
Absorb mineral ions required for healthy growth from very dilute solutions in the soil against a gradient
Active transport enable sugar molecules to do what?
Enables sugar molecules used for cell respiration to be absorbed from lower concentrations in the gut into the blood where the concentration of sugar is higher.
What is important in exchanging materials?
Surface area to volume ratio is very important as it helps with exchanging substances
What happens when an object get bigger
The ratio of surface area to volume falls
What is diffusion like in a small object?
Simple diffusion can happen in a small object as the distance is short for diffusion.
What is diffusion like in a large object
In a large object diffusion is not enough as the distance is bigger from the centre to the surface so diffusion is no longer long enough to exchange materials
How do organisms adapt to be as effective as possible?
Have a large surface area
Having a thin membrane to provide a short diffusion path
Having an efficient bloodstream moves the substances away from the exchange surfaces.
Having been ventilated makes gas exchange more efficient
Examples of adaptations in exchanging materials
Gills
Stomata
Alveoli
