B1 Key Concepts in Biology Flashcards
What are eukaryotes?
Organisms that contain more than one cell (animal and plants)
What are prokaryotes?
Single-celled organisms (bacteria)
What are in animal cells?
- Nucleus
- Cytoplasm
- Cell membrane
- Mitochondria
- Ribosomes
What are in plant cells?
- Nucleus
- Cytoplasm
- Cell membrane
- Mitochondria
- Ribosomes
- Rigid cell wall
- Large vacuole
- Chloroplasts
What are in bacteria cells?
- Chromosomal DNA
- Ribosomes
- Cell membrane
- Plasmid DNA
- Flagellum
What are specialised cells?
Cells that are adapted to their function
How are egg cells specialised for reproduction?
- Haploid nucleus
- Contains nutrients in the cytoplasm to feed the embryo
- Straight after fertilisation, its membrane changes structure to stop any more sperm getting in
How are sperm cells specialised for reproduction?
- Haploid nucleus
- Lots of mitochondria to provide the energy needed to swim a large distance
- Acrosome containing enzymes to digest the cell membrane of the egg cell
- Long tail to swim to the egg
How are ciliated epithelial cells specialised?
They have cilia with large surface area to ‘beat’ and move substances in one direction
What is an enzyme?
A biological catalyst
What factors affect the rate of reaction?
- Temperature
- pH
- Substrate concentration
What enzyme converts carbohydrates into simple sugars?
Amylase
What enzyme converts proteins into amino acids?
Protease
What enzyme converts lipids into glycerol and fatty acids:
Lipases
How do you test for reducing sugars?
Add Benedict’s reagent and heat in a water bath
What is the positive result for reducing sugars?
Brick-red precipitate
How do you test for starch?
Add iodine
What is the positive result for starch?
Blue-black
How do you test for lipids?
Add ethanol, shake, then pour in water
What is the positive result for lipids?
Cloudy precipitate
How do you test for proteins?
Add some potassium hydroxide and then some copper sulphate
What is the positive test result for proteins?
Purple
What is diffusion?
The overall movement of particles from an area of higher concentration to an area of lower concentration through a partially permeable membrane
What is osmosis?
The overall movement of particles from an area of higher water concentration to an area of lower water concentration through a partially permeable membrane
What is active transport?
The movement of particles across a membrane against a concentration using energy transferred during respiration
