Key Concepts Flashcards
What are animal cells?
These cells are eukaryotic. This means they have a nucleus
What is a cytoplasm?
where many of the chemical reactions happen.
What is a nucleus?
controls the cell’s activities.
What is cell membrane?
controls the movement of substances in and out of the cell
What is mitochondria?
where most energy is released in respiration.
What is a ribosome?
Tiny structures where protein synthesis occurs.
What is a plant cell?
These cells are eukaryotic.
What is a chloroplast?
Contains the enzymes needed for photosynthesis.
What is a cell wall?
Plant and bacterial cell walls provide structure and protection.
What is a permanent vacuole?
Filled with cell sap to help keep the cell swollen.
What is a bacteria cell?
The cells are all prokaryotic. This means they do not have a nucleus or any other structures.
What is chromosomal DNA?
The DNA of bacterial cells is found loose in the cytoplasm.
What is plasmid DNA?
Plasmid DNA can move from one bacterium to another giving variation.
What is flagella?
they move the bacterium.
How has a sperm cell adapted to carry out its function?
The middle piece is packed with mitochondria to release energy needed to swim and fertilize the egg. The tail enables the sperm to swim.
How has the egg cell adapted to carry out its function?
The cytoplasm contains nutrients for the growth of the early embryo. The haploid nucleus contains the genetic material for fertilization. The cell membrane changes after fertilization by a single sperm so that no more sperm can enter.
How has a Ciliated epithelial cell adapted to carry out its function?
Cilia on the surface beat to move fluids and particles up the trachea.
What is a light microscope?
light microscopes are used to study living cells and for regular use when relatively low magnification and resolution is enough
What is an electron microscope?
electron microscopes provide higher magnifications and higher resolution images but cannot be used to view living cells
How to calculate using a light microscope?
Magnification of the microscope = magnification of eyepiece × magnification of objective
How to calculate the magnification of an image?
magnification = size of image / real size of object
What are the two types of electron microscopes?
- the transmission electron microscope
2.the scanning electron microscope.
How many cm are in a meter?
100
How many mm in a meter?
1,000
How many micrometers in a meter?
1,000,000
How many nanometers in a meter?
1,000,000,000
What are enzymes?
Enzymes are proteins that function as biological catalysts. So, they are molecules that speed up a chemical reaction without being changed by the reaction.
What is the Lock and Key hypothesis?
In the lock and key hypothesis, the shape of the active site matches the shape of its substrate molecules. This makes enzymes highly specific.
What is an active site of an enzyme?
Enzymes are folded into complex 3D shapes that allow smaller molecules to fit into them. The place where these molecules fit is called the active site.
Why do enzymes denature?
If enzymes are exposed to extremes of pH or high temperatures the shape of their active site may change. If this happens they will no longer fit into the enzymes.
How to calculate rate of reaction?
Rate of reaction = amount of substrate used or amount of product formed ÷ time taken
How does the temperature effect the rate of reaction?
the rate of an enzyme-catalysed reaction increases as the temperature increases. However, at high temperatures the rate decreases again because the enzyme becomes denatured and can no longer function.
How does the pH effect the rate of reaction?
Changes in pH also alter the shape of an enzyme’s active site. Each enzyme work bests at a specific pH value. The optimum pH for an enzyme depends on where it normally works.
How does the substrate concentration effect the rate of reaction?
Enzymes will work best if there is plenty of substrate. As the concentration of the substrate increases, so does the rate of enzyme activity. However, the rate of enzyme activity does not increase forever.
What does a carbohydrate do?
break disaccharides and polysaccharides into monosaccharides (simple sugars)
What do proteins do?
Protease enzymes are responsible for breaking down proteins in our food into amino acids.
What do lipids do?
Digestive enzymes such as lipase break down lipids in the diet into fatty acids and glycerol. Lipase enzymes are produced in your pancreas and small intestine.
What are carbohydrates?
Carbohydrates include glycogen, starch, sucrose and glucose.
What are proteins?
They include enzymes, haemoglobin, collagen and keratin.
What are lipids?
Lipids are fats and oils. Lipids are large molecules made from smaller units of fatty acids and glycerol.
What is a Calorimeter?
measure the amount of energy in food
What is diffusion?
the movement of particles from a high to lower concentration.
What is osmosis?
Osmosis is the diffusion of water across a membrane.
What is active transport?
Active transport moves particles from low to higher concentration.
How does Concentration gradient affect the rate of diffusion?
The greater the difference in concentration, the quicker the rate of diffusion
How does the Temperature affect the rate of diffusion?
The higher the temperature, the more kinetic energy the particles will have, so they will move and mix more quickly
How does the surface area of the cell membrane affect the rate of diffusion?
The greater the surface area, the faster the rate of diffusion
How to calculate the rate of diffusion?
rate of diffusion = (surface area x concentration difference) / thickness of membrane.
How is Osmosis across living cells?
Cells contain dilute solutions of ions, sugars and amino acids. The cell membrane is partially permeable. Water will move into and out of cells by osmosis.
How is Osmosis in plant cells?
Isolated plant cells placed in a dilute solution or water will take in water by osmosis. If the soil is wet or moist then root hair cells will also take up water by osmosis.
How is Osmosis in animal cells?
Animal cells also take in and lose water by osmosis. They do not have a cell wall, so will change size and shape when put into solutions that are at a different concentration to the cell contents.
How to calculate the rate of water uptake?
water uptake in 1 hour = change in mass x (60mins / leng of experiment in mins)
How to calculate change in mass?
(mass at end - mass at start) / mass at start x 100
How to calculate ordered rank?
(percentile / 100) x number of entries in data set
What is active transport?
The movement of substances from a low concentration to a high concentration.
What substance is transported in diffusion?
Carbon dioxide, oxygen, water, food substances, wastes, eg urea
What substance is transported in Osmosis?
Water
What substance is transported in Active Transport?
Mineral ions into plant roots. Glucose from the gut into intestinal cells, from where it moves into the blood
