Key Concepts In Biology Flashcards
What is a eukaryote?
Cells with a nucleus
Eg animal and plant cells
What is a prokaryote?
A cell with no nucleus
Eg bacterial cells
What subcellular structures do plant cells have that animal plants don’t?
Vacuole
Chloroplast
Cell wall
What is the job of the nucleus?
Controls what happens in the cell and carries genetic info
What is the job of the cell membrane?
Controls what gets in and out
What is the role of the cytoplasm?
Jelly like substance where chemical reactions happen
What happens in ribosomes?
Proteins are made
What happens in mitochondria
Aerobic respiration
What happens in the vacuole?
Where cell sap is stored
What do chloroplasts do?
Photosynthesis occurs
What does the cell wall do?
Gives structure and support
What is a specialised cell?
A cell which is adapted to perform a specific function
What does the acrosome in a sperm cell do?
Breaks down the eggs jelly coat
What type of nucleus does a sperm cell have?
Haploid
What type of nucleus does an egg cell have?
Haploid
What happens to the cell membrane after fertilisation?
It closes to stop more sperm entering
What do cilia do?
They beat to and fro to move the egg towards the sperm
Where are cilia also found?
In the airways to move mucus away from the lungs
What does the chromosomal dna in a bacterial cell do?
Controls the cells activities
What is plasmid dna?
Small loops of extr dna in a bacterial cell
What is resolution?
The smallest distance between two points that can be seen as two points
What does better resolution mean?
More detail
What is the magnification equation?
Image size = actual size X magnification
What are the 4 units used in microscopy?
Millimetres
Micrometres
Nanometres
Picometres
What is an enzyme?
A protein that acts as a biological catalyst - speeds up chemical reactions
What are they molecules that enzymes work on called?
Substrates
Why are enzymes specific?
They only work with one specific substrate
How do enzymes speed up reactions?
The substrate binds to the active site of the enzyme, then the enzyme breaks down the substrate making 2 products
Types of enzymes
Carbohydrates are…
… enzymes break down carbs in our food
Carbohydrates are large molecules made out of lots of sugar molecules joined together
Carbohydrase enzymes
Types of enzymes
Proteins are…
… enzymes break down proteins in our food
Proteins are large molecules made out of lots of amino acids joined together
Protease enzymes
Types of enzymes
Lipids are…
…enzymes break down the fats in our food
Lipids are large molecules made out of lots of glycerol and fatty acids joined together
Lipase enzymes
What is the equation for rate of reaction?
Amount of product formed/time
If the temperature of enzymes is below the optimum, what happens?
There is more kinetic energy so the rate increases
If the temperature of an enzyme is above the optimum what happens?
The bonds in the enzyme break and the shape of the active site changes so much that the enzyme denatures
What happens when you change the pH of an enzyme a little?
Changes the shape of the active site, making the rate of reaction decrease, eventually denaturing
Describe substrate concentration
As the rate of concentration of substrate increases, the rate of reaction increases but only up to a point
After this, the rate plateaus (stays the same)
There are more substrates than enzymes
What is diffusion?
Passive movement of molecules from a high to low concentration
What is osmosis?
The passive movement of water molecules from a high to low concentration across a partially permeable membrane
What is active transport?
Movement of molecules from low to high concentration using energy from respiration so transport proteins can carry the molecules across the membrane
How do you investigate osmosis?
Tubes with different concentration of substrates in them
Equal sized piece of potato in each
Measure weight of potato before and after putting it in
