Key Concepts CB1 Flashcards
What is a eukaryotic cell?
They are complex and include all animal and plant cells
Cells that have a nuclei
What is a prokaryotic cell?
They are smaller and simpler and do not have nuclei in their cells
Nucleus
Contains dna and controls activity of cell
Cell membrane
Controls what goes in and out of the cell
Mitochondria
Where are aerobic respiration occurs - releases energy
Ribosomes
Where proteins are made in protein synthesis
Cytoplasm
Where chemical reactions take place
Chloroplasts
Contain chlorophyll to absorb sunlight where photosynthesis happens
Vacuole
Keeps the cell rigid support and stores sap
Cell wall
Made of cellulose for support and to stop the cell bursting
Chromosomal dna
Controls most of the cells activity and contains most of the cells dna
Plasmid dna
Small loops of extra dna
Contain some dna and controls some of the cells activity
Flagellum
A long hair like structure that rotates to make the bacterium move
Moves to propel the cell
What happens in sexual reproduction?
The nucleus of the egg fuses with the nucleus of the sperm to create a fertilised egg
They combine at fertilisation so the resulting cell will have 46 chromosomes
The main function of the egg cell
To carry the female dna and to nourish the developing embryo in the early stages
Cytoplasm in the egg
Contains nutrients to feed the embryo
What kind of nucleus does an egg cells have?
Haploid - 23 chromosomes
What happens to the eggs membrane after fertilisation?
It changes structure to stop any sperm getting in- makes sure the offspring end up with the right amount of chromosomes
What is the function of the sperm p?
Is to transport the males dna to the females egg
Why do sperms have a long tail?
To swim to the egg
Sperms mitochondria
Has lots in the middle section to provide the energy from respiration needed to swim the distance
What does the acrosome do in a sperm?
Stores enzymes needed to digest its way through the membrane of the egg cell
What kind of nucleus does a sperm have?
Haploid - 23 chromosomes
Where are epithelial cells found?
They line the surfaces of organs
What is the function of the ciliated epithelial cells?
To move substance- they beat to move substances in one direction along the surface of the tissue
How do you measure the actual size?
Image size / magnification
What is the actual size
Size in real life
What is the image size?
Size on the picture
What is the magnification?
How much bigger the image is then the actual size
What was Robert Hookes microscopes magnification?
X30 this means that the object became 30 times bigger than the actual size
What are better old or new light microscopes?
New as they have a better magnification- this allows us to see small objects
They have better resolution as well
What is the eye piece lens on a light microscope?
The eyepiece lens magnifies the image
What is resolution?
The smallest distance between two points that can be seen as two points
- a better resolution allows us to see in more detail
What are electron microscopes?
They are the most modern
They have better magnification of x2000000 and resolution
What are micrographs?
Pictures taken down by micro graphs
What is it called that you see down the micro scope?
The field of view
How do you use the microscope?
Place the slide on the stage and look through the eyepiece lens
Make sure the smallest objective lens is on
Turn the focussing wheel to get a clear image
Increase the magnification of the objective lens and use the focussing wheel again
What is an enzyme?
A protein that acts as a biological catalyst. It speeds up chemical reactions without being changed itself
What is the active site?
The part where it joins on to its substrate to catalyse the reaction.
What happens if you increase the temperature in an enzyme reaction?
Increase the rate at first
But if it gets to hot some of the bonds holding the enzyme together break
This changes the shape of the enzymes active site
The enzyme denatures
What affect does the pH have on enzymes?
If it’s to high or low the pH interferes with the bonds holding the enzyme together - changes the shape of the active site and enzyme denatures
What’s the effect of pH on Pepsin?
Pepsin breaks down proteins in the stomach - it works best at pH 2 which means it’s well suited in acidic conditions
What is the effect of the substrate concentration?
The higher the substrate concentration, the faster the reaction. This is because it is more likely for an enzyme to meet up and react with a substrate molecule
However after a point, adding more makes no difference
What are carbohydrates made out of?
What enzyme breaks it down?
What does it break down into?
Sugar molecules joined together
Carbohydrase breaks food down in digestion into sugars so we can absorb them into our blood
What are proteins made out of?
What enzyme breaks them down?
What do they break down into?
Amino acids
Protease
Into amino acids so we can absorb them into out blood
What are lipids made up of?
What enzyme breaks them down?
What do they break down into?
Glycerol and fatty acids
Lipase
Into glycerol and fatty acids so we can absorb them into our blood
What is glycogen synthase?
An enzyme that joins together lots of chains of glucose molecules to make glycogen
Diffusion
Is the overall movement of particles from an area of high concentration to an area of low concentration
What substances can diffusion happen in?
Liquids and gases because the particles are free to move about randomly
What is osmosis?
The net movement of water molecules across a partially permeable membrane from a region of high per water concentration to a region of lower concentration
What is active transport?
The movement of particles across a membrane from an area of low concentration to an area of high concentration using energy transferred during respiration
Slime coat
Stops cell from drying out and protects it from being engulfed
Acrosome
Contains enzymes to break down the jelly coat to allow the sperm to get inside and fertilise the egg
Cytoplasm in a the egg cells
Contains lots of nutrients for the fertilised egg to use to help it develop into an embryo
Cell membrane of the egg
Hardens after fertilisation to prevent more than one sperm entering
Ciliates epithetical cells in fertilisation
Have cilia which are hair like structure that beat to and fro to move the fertilised egg towards the womb
