Flashcards in Key Concepts Deck (67):
What are eukaryotes?
Complex: animal and plant cells
What are prokaryotes?
Small & simple: bacteria
Contains genetic material
Controls the activities of the cell
Genetic material arranged into chromosomes
Chemical reactions happen
Holds the cell together
Controls what goes in and out
Where most of the reactions for respiration happen
Powerhouse of the cell
Involved in translation of genetic material in protein synthesis
Made of cellulose
Supports cell and strengthens it
Contains cell sap
Weak solution of sugar and salts
Internal pressure to support cell
Where photosynthesis occurs
Makes bait for the plant
Controls cells activities & replication
Floats free in cytoplasm
Small loops of extra DNA
Genes for drug resistance
Long hair like structure
Rotated to make bacterium move
Move bacteria away from harmful substances
What are the 2 cells used in sexual reproduction?
What’s the main function of the egg cell?
Carry the females DNA and to nourish the developing embryo in early stages
Why is there nutrient in the cytoplasm of an egg cell?
To feed the embryo
What is a haploid cell?
A cell that only contains half the number of chromosomes of a normal cell
What happens in the egg cell straight after fertilisation?
It’s membrane changes structure to stop any more sperm getting in.
Therefore the offspring gets the right amount of DNA
What is the function of the sperm cell?
Transport the males DNA to the females egg
Why does a sperm cell have a long tail?
So it can swim to the egg
Why does a sperm cell have a lot of mitochondria in the middle section?
To provide the energy needed to swim this distance
What is an acrosome?
The front of the head of a sperm cell where it stores enzymes to digest it’s way through the membrane of the egg cell
Where are epithelial cells found?
Lining the surfaces of organs
What is cilia
Hair like structures
What do epithelial cells do?
Move substances in one direction along the surface of the tissue
How do you work out magnification
Image size ➗ real size
How do you calculate total magnification?
Eyepiece lens magnification x objective lens magnification
What are enzymes?
Catalysts produced by living things
What is a catalyst?
A substance which increases the speed of a reaction without being changed or used up in the reaction.
What type of catalyst is an enzymes found in living things?
Why do enzymes have special shapes
So they can catalyse reactions
What do chemical reactions usually involve?
Being split apart or joined together
What is a substrate
The molecule changed in a reaction
What is an active site?
The prt where the enzyme joins on to its substrate to catalyse the reaction
What is the lock and key mechanism?
The substrate must fit into the active site and if it doesn't, the reaction won't be catalysed. If it fits I'm looks like how a key fits into a lock.
What can affect the rate of reaction for enzymes
What happens when an enzyme becomes denatured?
The enzyme has become too hot/ too high/low pH
The bonds holding the enzyme together have broken
The active site of the enzyme has changed
Substrate no longer fits
What is an optimum temperature/pH
What temperature/pH the enzyme works best at
What happens if there is a high substrate concentration?
The reaction will be faster
How do you calculate the rate if reaction
Why is it important organisms can break down big molecules?
So they can be used for growth and other life processes
What do plants store energy in the form of?
What happens when plants need energy?
Enzymes break down starch into smaller molecules (sugar)
Carbohydrates into simple sugars
Starch *amylase* ➡️ maltose and other sugars
Proteins into amino acids
Proteins *protease enzymes* ➡️ amino acids
Lipids into glycerol and fatty acids
Lipid *lipase enzymes* ➡️ glycerol and fatty acids
How are carbohydrates synthesised
By joining together simple sugars
How are proteins made
By joining amino acids together
How do you test for sugars
Using Benedict's Reagent
If there's sugar what colour will Benedict's reagent turn to
Blue ➡️ Red
What is used to test for starch
What happens to iodine solution if starch is present
It changes from browny orange to dark blue-black colour
What is the test for lipids
The emulsion test
What is the substance used to test for lipids
What happens if lipids are present when mixed with ethanol?
The liquid will go milky when shook
What is the proteins test?
The biuret test
What do you add to the substance to test for proteins
What colour will the solution turn in the biuret test if protein is present
Blue ➡️ purple
How do you test to see how much energy bait contains?
Burn it (calorimetry)
How do you calculate energy in food?
Mass of water x temperature change in water x 4.2
How do you work out how much energy per grams of food there is
Energy in food/ mass of food
What is diffusion
The movement of particles from an area of high concentration to low concentration
What size molecules can be diffused through cell membranes
What is osmosis
The movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration
What is a partially permeable membrane
A membrane with small holes
What is active transport
The movement of particles across a membrane against a concentration gradient using energy transferred during respiration.