B1. Cells and Movement of substances Flashcards
How do you calculate total magnification of a micropscope?
Total magnification = Eyepiece lens x objective lens
Define the term resolution
Resolution is the ability to distinguish between two separate points in an image
What is the function of the nucleus?
Contains DNA in the form of chromosomes. Controls the cell.
What is the function of the cytoplasm in a cell?
This is where chemical reactions take place
What is the function of the cell membrane?
Controls what enters and leaves the cells.
What is function of the mitochondria in cells?
This is the site of respiration. Glucose + Oxyen –> Carbon dioxide + water vapour + ATP energy
Define the word ‘magnification’.
Magnification is how much bigger an image is compared to it’s actual size. Can be calculated by using the IAM triange.
What is the function of the cellulose cell wall?
This is outer layer of plant cells. It is made of cellulose. It gives the plant strength and support.
Why are ribosomes needed in a cell?
Ribosomes are the site (location) where proteins are made.
What is the function of chloroplasts in plant cells?
Chloroplasts contain a green chemical called chlorophyll. It traps sunlight energy which is needed for photosynthesis.
What type of microscope could be used for viewing for small organelles e.g. ribosomes?
Electron microscope
What type of DNA do prokaryotic cells have?
1 circular chromosome, NOT enclosed by a nucleus.
What type of DNA do eukaryotic cells have?
Many linear chromosomes enclosed by a nucleus.
Define the term ‘diffusion’.
Diffusion is the net random movement of particles from an area of high concentration to an area of low concentration.
Define the term ‘osmosis’.
Osmosis is the net random movement of WATER from an area of high concentration to an area of low concentration, across an PARTIALLY PERMEABLE MEMBRANE.
What is meant by a passive process?
A passive process does not require ATP energy.
What is meant by an active process?
An active process requires ATP energy from respiration.