All of igcse bio

Created by

Kemkem Elegbe

Cards (163)

What is the basic unit of life?
Cells
What does an electron microscope allow us to see?
Finer details of organelles.
How can we calculate the actual size of a cell using a microscope?
By dividing the image size by the magnification.
What are the two main groups of cells?
Eukaryotic cells and prokaryotic cells.
What is a characteristic of eukaryotic cells?
They have a nucleus containing DNA.
Where is DNA found in prokaryotic cells?
In a ring called a plasmid.
What is the function of the cell membrane?
It keeps everything inside the cell and is semi-permeable.
What do plant cells and most bacteria have that provides a rigid structure?
A cell wall made of cellulose.
What is the cytoplasm?
The liquid that makes up the cell where most chemical reactions occur.
Where does respiration take place in a cell?
In the mitochondria.
What is the role of ribosomes in a cell?
They assemble or synthesize proteins.
What do chloroplasts contain and what is their function?
They contain chlorophyll and are where photosynthesis takes place.
What is a permanent vacuole in plant cells used for?
To store sap.
What are stem cells?
Cells that haven't yet specialized.
Where are stem cells found in humans and animals?
In embryos and bone marrow.
How can stem cells be used in medicine?
To combat conditions like diabetes and paralysis.
What ethical considerations are associated with cloning?
Cloning raises ethical arguments regarding its implications and consequences.
What is diffusion?
The movement of molecules from an area of high concentration to an area of low concentration.
What is osmosis?
The diffusion of water across a semi-permeable membrane.
How does the concentration gradient affect diffusion and osmosis?
A greater difference in concentrations increases the rate of diffusion and osmosis.
What factors can increase the rate of diffusion and osmosis?
Increasing concentration difference, temperature, or surface area.
What is the practical procedure for investigating osmosis using potato cylinders?
Cut equal size cylinders from a potato.
Weigh them and place in test tubes with varying sugar concentrations.
After a day, remove and dab excess water.
Reweigh and calculate percentage change in mass.
Plot percentages against sugar concentration.
What is active transport?
The movement of substances against a concentration gradient using energy.
What is the function of tissues in the body?
To organize similar cells together.
How do organs function in an organ system?
They work together to perform specific functions.
What is the role of the stomach in digestion?
It breaks down food using acid.
What is the function of bile in digestion?
To neutralize stomach acid and emulsify fats.
What are enzymes?
Biological catalysts that speed up chemical reactions.
How do enzymes work on substrates?
They bind to specific substrates at their active site to form a complex.
What happens to an enzyme when it denatures?
The active site changes shape, preventing substrate binding.
What is the optimum temperature for enzyme activity?
The temperature at which the enzyme works best.
What is the role of carbohydrates in a balanced diet?
To provide energy.
What are the consequences of vitamin C deficiency?
It can lead to scurvy, affecting gums and hair.
What is the function of calcium in the body?
To maintain healthy bones.
What is the role of fiber in the diet?
To keep the digestive system working properly.
What is the function of the respiratory system?
To facilitate breathing and gas exchange.
How does oxygen enter the blood during respiration?
It diffuses from the alveoli into the blood vessels.
What is the role of hemoglobin in red blood cells?
To bind oxygen for transport.
What happens to carbon dioxide produced during respiration?
It diffuses into the lungs and is exhaled.
What is the structure of the heart?
It has four chambers: right atrium, right ventricle, left atrium, and left ventricle.