CB1 Flashcards
What is the formula triangle for magnification?
Image size
Actual size | Magnification
Define ‘Biological Catalyst’
A substance found in a living organism that speeds up reactions, i.e an enzyme.
Describe the process of Active Transport?
The process is carried out by transport proteins in cell membranes. The transport proteins capture certain molecules and carry them across the cell membrane changing shape and using its energy.
Why would the time taken to complete a reaction start to increase again after reaching an optimum temperature?
The time taken to complete digestion has started to increase again as the enzyme has passed its optimum temperature for a reaction and the enzyme used for digestion is starting to denature, slowing the time taken for a reaction once again.
Give two adaptations egg cells have for reproduction?
- The cell membrane hardens after fertilisation to ensure that only one sperm cell enters the egg cell.
- The cytoplasm is packed with nutrients to supply the fertilised egg cell with energy and raw materials for the growth and development of the embryo.
Give two adaptations that Sperm cells have for reproduction?
- A large tail that waives side to side, allowing them to swim and have mobility.
- The tip of the head contains a small vacuole (acrosome) which contains enzymes that break down the substances in the egg’s jelly coat, allowing the sperm to burrow inside.
How are enzymes adapted for digestion?
When the pancreas makes enzymes, they are made in order to digest certain food in the small intestine. The enzymes are proteins and so these cells are adapted by having a lot of ribosomes.
How do you identify the optimum tempurature/pH of an enzyme?
It is when the rate of reaction is the highest/It is when there is the least time taken to complete a reaction.
How does the concentration of substrates affect the rate of reaction?
The rate of reaction is slow at low concentrations as many enzymes have empty active sites whereas at high concentrations, most enzymes contain substrates, so the rate of reaction is the fastest it could possibly be.
How has the small intestine adapted for digestion?
It has adapted by having membranes with many tiny folds (called Microvilli). The outer membrane is folded to form Microvilli which increases the surface area of the cell, allowing it to absorb more small food molecules.
How have ciliated epithelial cells adapted for reproduction?
Ciliated epithelial cells have hair-like structures called Cilia which wave from side to side to sweep substances (like egg cells travelling to the uterus) with great speed.
Name three parts that all bacteria typically have?
- Chromosomal DNA strands
- Flagellum
- Cytoplasms
State three differences between Haploid and Diploid cells?
- Haploid cells contain one set of chromosomes while Diploid cells contain two sets of chromosomes.
- Haploid cells are formed from Meoisis while Diploid cells undergo Mitosis.
- Haploid cells are only present for gametes while Diploid cells are present for all other types of cells.
What are the three methods of transporting substances?
- Diffusion
- Osmosis
- Active Transport
What are three differences between light and electron microscopes?
- Electron microscopes have a higher power of magnification (can magnify more)
- Samples are always dead in electron microscopes but can be alive in light microscope.
- Electron microscopes provide black and white images of the magnification whereas Light microscopes produce coloured images of the magnification.
What direction are particles transported in Active Transport?
Against the concentration gradient (From areas of low concentration to areas of high concentration)
What directions do particles move in diffusion?
They move down the concentration gradient (from areas of higher concentration to areas of lower concentration)
What do protein molecules, starch molecules and lipid molecules break down to become?
- Protein molecules break down (digestion) to make amino acids
- Starch molecules break down (digestion) to make glucose molecules
- Lipid molecules break down (digestion) to make fatty acids and glycerol.
What does it mean when an enzyme is denatured?
An enzyme is denatured when the shape of the active site changes to the point where no substrate can fit into it. This typically happens once changes in pH or temperature happen after a reaction.
What does Prokaryotic mean?
It means that their cells do not have nuclei or chromosomes. Instead, the cytoplasm contains one large loop of chromosomal DNA, which controls most of the cells activities (Bacteria are prokaryotic)
What is a real life example of diffusion?
When it allows small molecules (such as Oxygen or Carbon Dioxide) to move into and out of cells such as plant cells.
What is the active site of an enzyme?
It is where the substrate of the enzyme fits at the start of a reaction.
What is the function of Cell Membrane in Animal and Plant cells?
It is like a thin bag which controls what enters and leaves the cell, as well as separating one cell from another.
What is the function of Chlorplasts in Plant cells?
They contain Chlorphyll, which traps energy transferred from the sun. This energy is used for the process of Photosynthesis (It is where photosynthesis occurs)
What is the function of Cytoplasms in Animal and Plant cells?
It contains a watery jelly and is where most of the cells activities occur.
What is the function of Mitochondrion in Animal and Plant cells?
They are jelly-bean shaped structures in which aerobic respiration occurs (it is the site of aerobic respiration)
What is the function of Ribosomes in Animal and Plant cells?
They are tiny, round structures which make new proteins for the cell.
What is the function of the nucleus in Animal and Plant cells?
The nucleus controls the cells and its activities. Inside it are chromosomes which contain DNA (which carry around genetic information)
What is the function of Vacuoles in Plant cells?
They store cell sap and help keep the cell firm and rigid.
What is the order of the prefixes?(go in order from biggest to smallest and multiply by 1000 each time)
Millimeter (mm), Micrometer (μm), Nanometer (nm), Picometer (pm)
What type of processes are ‘Diffusion’, ‘Osmosis’ and ‘Active Transport’ (Do they require an input of energy for transport)?
Diffusion = Passive process (No input of energy needed)
Osmosis = Passive process (No input of energy needed)
Active Transport = Active process (Input of energy needed)
Where does Osmosis occur and in what direction do the particles go in?
Osmosis occurs in a solvent (such as water) and the particles move down the concentration gradient (from areas of low concentration to areas of high concentration)
Why can only specific substrates fit into the active site of an enzyme?
This is because the active sites have different shapes that only match the substrate that is meant to react with the enzyme by going into the active site.
How has temperature affected mean glucose concentration in a potato chip? (CB1h practical)
The mean number of glucose increased with the shape of the graph until it reached 40°c then it starts to decrease. This might be because the enzyme is starting to denature, meaning 40°c is it optimal temperature for the reaction of Osmosis in this potato chip.
What happens in Osmosis when the Salt concentration is at 0%? (CB1h practical)
Water moves passively by Osmosis down its concentration gradient into the potato chip, increasing the mass of the potato chip.
What happens in Osmosis when the Salt concentration is at 50%? (CB1h practical)
No concentration gradient and no change in mass because no net movement of water as the concentration is already equal.
What happens in Osmosis when the Salt concentration is at 100%? (CB1h practical)
Water moves passively by Osmosis down its concentration gradient out of the potato chip, decreasing the mass of the potato chip.
What are: independent, dependent and controlled variables?
Independent: A variable that changes.
Dependent: A variable that you measure.
Controlled: A variable that stays the same.
How do you use a microscope to examine cells? (CB1b practical)
- Get a small sample of a cell.
- Add a small drop of water at the centre of the microscope slide (As this makes the cell translucent instead of transparent)
- Put the sample cell on the drop of water.
- Use a toothpick to slowly lower a coverslip onto the cell, which keeps it flat. This is so it stays in place and doesn’t dry out.
- Examine the cell under a microscope and sketch what you see on a piece of paper.
What are the independent, dependent and controlled variables in a pH experiment? (CB1g practical)
Independent: The pH of the solution
Dependent: Time taken for the substrate to break down
Controlled: The temperature of the solution
What apparatus is needed for a pH experiment? (CB1g practical)
A tripod, Gauze, Heat-resistant mat, Bunsen burner, Large beaker.
What are the independent, dependent and controlled variables in an Osmosis in potato slices experiment? (CB1h practical)
Independent: Concentration of Salt/Sucrose
Dependent: The mass of the potato slice
Controlled: The solution that the potato chip is dipped in
What enzyme breaks down lipids?
Lipase.
