Biolodgy Revison S3 Flashcards
Function of the cell membrane
controls what enters and leaves a cell
Function of the cytoplasm
Site of chemical reactions in the cell.
Function of the nucleus in an animal cell
Controls the cell’s activities
Where in an animal cell does protein synthesis occur?
Ribosome
Function of the vacuole in a plant cell
Stores cell sap and maintains cell shape.
Function of the cell wall in plant, bacterial and fungal cells
Provides support and gives structure to the cell.
Where in the cell does aerobic respiration occur?
Mitochondria
Which cell structure is the site of photosynthesis?
Chloroplast
Give three structures that are found in both plant and animal cells
Nucleus Cytoplasm Cell membrane
Give two structural differences between plant and animal cells
A plant cell has a cell wall and chloroplasts , an animal cell does not
Give two differences between an animal and a bacterial cell
A bacterial cell has a cell wall and a plasmid, an animal cell does not
What substance is the main component of plant cell walls?
Cellulose
Why do scientists use a stain when viewing cells under a microscope?
Stains enable us to see cells more clearly when viewing under a microscope.
What would the overall magnification be if the x40 objective lens was used to view cells?
400
What would the overall magnification be if the X10 objective lens was used to view cells?
100
A plant cell is 60μm in length, how many millimetres is this?
0.06mm
What is a plasmid, and in which type of cell is it found?
Small, circular pieces of genetic material that can be transferred between organisms. Found in bacterial cells.
What is diffusion?
Diffusion is the movement of molecules from an area of high concentration to an area of low
concentration until they are evenly spread.
In what kind of substances does diffusion occur?
Solid,liquid and gas
Why is diffusion able to happen in a gas?
Diffusion happens in gases as the particles move freely and quickly therefor bump into eachother.
Why does diffusion happen very slowly in a solid?
The particles are fixed
Name 2 substances that are needed by cells
Oxygen and glucose
Name 1 waste product produced by cells
Carbon dioxide
Why does the litmus paper turn from red to blue?
It shows the change from an area of high concentration to an area of low concentration until the molecules were evenly spread
Why would oxygen move into a cell?
aerobic respiration.
Why would glucose move into a cell?
provide energy to make ATP during aerobic respiration.
What is a concentration gradient?
A concentration gradient occurs when the concentration of particles is higher in one area than another.
What is a catalyst?
A substance which speeds up a chemical reaction, without being altered or changed during the process.
Describe the effect of increasing temperature on enzyme activity
Increasing temperature increases enzyme activity and the reaction rate until the enzyme’s optimum temperature is reached. Different enzymes have different optimum temperatures.
Explain how Amylase functions to speed up the breakdown starch
Amylase allows the starch molecule to break down into many smaller maltose molecules
An experiment was set up to investigate the effect of pH on enzyme activity. Give three variables
that would have to be kept constant when carrying out this experiment.
Volume of pH, tools used and time taken.
What is the difference between the independent variable and the dependent variable in an
investigation?
The variable that is being purposely altered in an investigation and the variable is being measured in an investigation to get the results. The dependent variable changes because of the changes made to the independent variable.
Explain why Catalase is the only enzyme that can catalyse the breakdown of hydrogen peroxide
Catalase is specific to hydrogen peroxide
What is meant by the term ‘biological catalyst’
An enzyme is a biological catalyst and is almost always a protein. Speeds up the chemical reaction
What is the name given to the part of an enzyme where the substrate binds?
Active site
Name the subunits of protein molecules
Amino acids
Describe what happens when an enzyme denatures?
When the shape of a protein molecule irreversibly changes. This can be caused by high temperatures or a pH outside the working range.
Name the enzyme that speeds up the breakdown of Hydrogen peroxide?
catalase
What is meant by ‘optimum pH’?
The conditions e.g. temperature or pH, at which a reaction will occur at the fastest rate.
What could be done to make the results of an experiment more reliable?
Repeat the experiment.
The working pH range of Catalase is pH 6-9, but it’s optimum is pH 7. Explain what would happen
to the activity of Catalase if pH was increased from 6 to 11.
The catalase stops working
What name is given to the molecule which an enzyme acts on?
substrates
What is a degradation reaction?
A reaction in which a large molecule is broken down into one or more smaller molecules.
Name the substance from which all enzymes are made
amino acids
