Biology End Of Years Year 9 Collegiate Flashcards
What is the nucleus?
The nucleus contains genetic instructions (DNA) which controls the cell’s activities
What happens in ribosomes?
Protein synthesis, by linking amino acids
What happens in mitochondria?
Respiration, to release energy for the cell to use
What is the purpose of cytoplasm?
To hold organelles and to be the place where most chemical reactions happen
What would be the substance used to show cheek cells more clearly?
Methylene blue
What are the two focus wheels on a microscope called?
Coarse (for large adjustments) and fine focus (for minor adjustments)
What is the formula to calculate magnification?
eyepiece lens x objective lens
What do chloroplasts contain that make them green?
Chlorophyll
What is the purpose of a cellulose cell wall?
To strengthen the cell and provide support
What is the purpose of a vacuole?
Storing cell sap to keep the cell rigid
What is an object? (in microscope terms)
The real specimen that can be seen and touched
What is an image? (in microscope terms)
A visual representation of the specimen (object)
What is the definition of magnification?
How many times bigger the image is compared to the object
What is the definition of resolution?
The ability to see two points that are close together, apart
What is the formula to work out the size of the image?
I (mm) = A x M
What does A stand for?
Size of actual object (micrometres)
What does M stand for?
Magnification
What is osmosis?
The net movement of water particles from an area of high concentration to an area of low concentration, down a water concentration gradient through a selectively permeable membrane until water equilibrium is reached
How do you calculate % change?
(Change in mass / start mass) x 100
What is the definition of hypotonic?
More water outside the cell than in the cytoplasm so there is less solute
What is the definition of isotonic?
As much water outside the cell as in the cytoplasm
What is the definition of hypertonic?
Less water outside the cell than in the cytoplasm so there is more solute
What is the definition of active transport?
The movement of molecules against the concentration gradient from an area of low concentration to an area of high concentration using energy from cellular respiration and protein carriers in the membrane
Why can water move through cell membranes?
Because it is so small
What 3 things do bacterial cells have that are different to plant cells?
Pili, flagella and a slime capsule
Why do exchange surfaces feature a large surface area?
There is more surface so the rate of movement is faster
Why do exchange surfaces feature a thin membrane?
So that there is a shorter diffusion distance
Why is there always a moving blood supply near exchange surfaces?
It keeps a steep concentration gradient
Why are exchange membranes moist?
It helps gases to diffuse faster
What 4 elements do proteins contain?
Carbon, hydrogen, oxygen and nitrogen
What is the test for starch?
Iodine solution
What colour does iodine solution turn if a starch is present?
Blue/black
What is the test for sugar?
Benedict’s
What colour does Benedict’s turn if sugar is present?
Brick red
What is the test for protein?
Biuret’s
What colour does biuret’s turn if protein is present?
Purple
What is the test for lipids?
Ethanol
What colour does the ethanol turn if lipids are present?
Milky white
What are 4 functions of proteins?
- Structural e.g. muscle, hair, nails
- Biological catalysts - enzymes e.g. salivary amylase
- Immune response - antibodies
- Chemical messengers - hormones e.g. insulin
What happens in the mouth?
Teeth break food into smaller chunks, saliva breaks the bonds of some food and the tongue helps to move the food done the oesophagus
