whole of paper 1

Created by

sarah siv

Cards (263)

What is the difference between eukaryotic and prokaryotic cells?
Eukaryotic cells have a nucleus, while prokaryotic cells do not
What structures can be seen with a light microscope?
Cells and possibly the nucleus
What is the role of an electron microscope?
It allows us to see finer details of organelles
How can you calculate the actual size of a cell using a microscope?
By dividing the image size by the magnification
What is the function of the cell membrane?
It keeps everything inside the cell and is semi-permeable
What is the composition of the cell wall in plant cells?
Cellulose
What is the function of mitochondria in a cell?
It is where respiration takes place, releasing energy
What do ribosomes do in a cell?
They assemble or synthesize proteins
What is the role of chloroplasts in plant cells?
They contain chlorophyll and are where photosynthesis takes place
What is a permanent vacuole in plant cells used for?
It stores sap
How do bacteria multiply?
By binary fission
What is the procedure for culturing bacteria on agar using aseptic technique?
Lift the lid of the dish towards a flame to move microbes away
Use sterilized equipment to place bacteria culture on agar
Tape the lid on loosely to allow air in
Incubate at 25°C
How do you calculate the area of a circle in a bacterial culture?
Using the formula $A =$ $\frac{\pi d^2}{4}$
How many pairs of chromosomes do humans have?
23 pairs
What is the difference between diploid and haploid cells?
Diploid cells have 23 pairs of chromosomes, while haploid cells have 23 single chromosomes
What is the process of mitosis?
It is the duplication of genetic material and division to form two identical cells
Where are stem cells found in humans?
In human embryos and bone marrow
What are the potential uses of stem cells?
To combat conditions like diabetes and paralysis
What ethical considerations are associated with stem cell research?
Concerns about cloning and the implications of creating life
What is diffusion?
It is the movement of molecules from high to low concentration
What is osmosis?
The diffusion of water across a semi-permeable membrane
How can the rate of diffusion be increased?
By increasing concentration difference, temperature, or surface area
What is the practical procedure for investigating osmosis using potato cylinders?
Cut equal size potato cylinders and weigh them
Place in test tubes with varying sugar concentrations
After a day, weigh them again
Calculate percentage change in mass
Plot results against sugar concentration
What is active transport?
The movement of substances against a concentration gradient using energy
What is the role of enzymes?
They act as biological catalysts to speed up chemical reactions
What is amylase and its function?
Amylase is an enzyme that breaks down starch into glucose
What is the lock and key principle in enzyme activity?
It describes how substrates fit into an enzyme's active site
What happens to an enzyme when it denatures?
The active site changes shape, preventing substrate binding
How does temperature affect enzyme activity?
Increased temperature increases activity until denaturation occurs
What is the function of bile?
To neutralize stomach acid and emulsify fats
What is the role of the small intestine in digestion?
It absorbs nutrients into the bloodstream
What color does iodine turn in the presence of starch?
Black
What color does Benedict's solution turn in the presence of sugars?
From blue to orange
What happens to cold ethanol in the presence of lipids?
It turns cloudy
What is the process of breathing?
It provides oxygen necessary for respiration in cells
What is the role of alveoli in the respiratory system?
They facilitate gas exchange between air and blood
What is the structure of the heart?
It has a right and left side, with atria and ventricles
What is the function of valves in the heart?
To prevent backflow of blood
What is the role of the coronary artery?
To supply blood to the heart muscle
What is coronary heart disease (CHD)?
It is caused by the buildup of fatty deposits in coronary arteries