Key Concepts In Bioligy Flashcards
A plant cell, a prokaryotic cell, or a eukaryotic cell
Eukaryotic cell
In which sub cellular structures, do most of the reactions for respiration take place
Mitochondria
Which sub cellular structure maintains the internal pressure in a Plant cell
Vacuole
Describe the main similarities and differences between a bacterial cell and a plant cell
Similarities: both have a cell membrane, a cell wall, cytoplasm and ribosomes
differences: plant cells have chloroplasts and mitochondria, but bacteria do not, the chromosomes of a plant cell are contained within the nucleus where as bacteria have chromosomal DNA that floats freely in the cytoplasm, bacterial cells may also contain small loops of extra DNA called plasmids
Where are ciliated epithelial cells found
On the surface of organs
Give two functions of an egg cell
To carry the female DNA and to provide nutrients to the embryo in early stages
Why do sperm cells contain a large number of mitochondria?
Provide energy (from respiration) needed to swim to the egg
Why is it important that egg and sperm cells are haploid?
So that when an egg cell and a sperm cell nucleus combine at fertilization the resulting cell will have the right number of chromosomes (haploid cells only have half the chromosomes of a normal body cell)
Describe how ciliated epithelial cells are adapted for moving substances
They have Celia, which beat to move substances in one direction along the surface
Why does the structure of an eggs cell membrane change after fertilization?
To stop any more sperm getting in ,making sure that the offspring end up with the right amount of DNA
What is the purpose of the fine adjustment knob on a light microscope?
It’s used to focus the lens until a clear image of what’s on the slide appears
True or false? electron microscope’s have a smaller magnification than light microscope’s, but they have a higher resolution than light microscope’s
False
Describe how you would put a cover slip onto a specimen on a slide, so that it’s ready to be viewed under a light microscope
The cover slip should be placed at one end of the specimen, and held at an angle with the mounted needle. It should then be carefully lowered onto the slide and pressed down gently, so that no air bubbles are trapped under.
How has electron microscopy increased our understanding of cells?
The high magnification and high resolution has allowed biologists to see very small structures in detail like the internal structure of mitochondria and chloroplasts. This has allowed biologists to better understand how cells work, and give us a greater understanding of the role of sub cellular structures
Is a pico meter smaller or larger than a nanometer
Smaller
What is the formula to calculate the microscope’s total magnification?
Image size = actual size X magnification
Magnification = image size/actual size
Image size = magnification/actual size
Why might a student want to estimate the size of a protist as well as calculating it with a Calculator?
To ensure the answer they get with a Calculator is sensible
How do you enzymes affect the rate of Reaction
Enzymes increase the rate of reaction and act like a biological Catalyst
What is an active site of an enzyme?
The part of the enzyme which joins onto its substrate to catalyze the reaction
True or false? enzymes usually only work with one substrate
True
What are some variables that affect the rate Rate of an enzyme catalyzed reaction
Temperature, pH and substrate concentration
What happens to an enzyme when it’s denatured?
Some of the bonds holding the enzyme together a break, and the shape of its active site changes. This means that the substrate won’t fit so the enzyme can no longer catalyze a reaction anymore.
True or false? pH is the dependent variable in an experiment investigating how pH affect enzyme activity
False
In an experiment investigating how pH affects Emily’s activity, what would you use to test for the presence of starch?
Iodine solution
A student is investigating the effect of pH on the rate of amylase activity. Suggest how the student could control the temperature of the amylase and starch solution during the experiment.
The student could put a test tube containing the solution in a beaker of water over a Bunsen burner and use a thermometer to help keep the water at a constant temperature. Alternatively, the student could use an electric water bath.
The student uses continuous sampling to record how long it takes for the amylase to break down all of the starch .what is continuous sampling?
Continue sampling is When Lots of samples are taken at regular intervals over a particular time Period.
Which type of molecule are proteins broken down into
Amino acids
What type of enzyme breaks down proteins?
Proteases
Vikash is eating rice, which contains a lot of the carbohydrate starch. name the type of enzyme that will break down the starch during digestion
It will be broken down into carbohydrases
How are carbohydrates synthesized?
Simple sugars are joined together to form carbohydrates in a process catalyzed by enzymes
Why is it important that organisms are able to break down big molecules into smaller molecules?
Big molecules are unable to pass through the wall of the digestive system and can’t be absorbed into the bloodstream. Small molecules can pass through and be absorbed, which means they can pass through and be absorbed , which means they can then pass into cells and be used for growth and other life processes.
True or false? oxygen entering the blood from the lungs is an example of osmosis
False. It happens by diffusion osmosis, involves the movement of water molecules
What type of membrane is needed for osmosis to happen?
A partially permeable membrane
When plants lose water, they start to wilt explain why most plants will wilt if the soil they are growing and is flooded with salty sea water
Due to the seawater, having a high concentration of salt, the water concentration in the soil will be lower than in the plant. This means water will move by osmosis causing the plant to lose water and wilt
Oxygen diffuses from the bloodstream into muscles. during exercise oxygen is used up in the muscles faster than when a person is at rest suggest how the rate of oxygen diffusion might affect when a person is running, compared to when they are sitting down
Diffusion rate will be greater when the person is running compared to when the person is sitting down this means that there will be a lower concentration of oxygen in the muscles as it is used up quicker meaning there will be a greater concentration gradient, and so a faster rate of diffusion
How does water concentration change as solute concentration increases
The water concentration of a solution decreases as the solute concentration increases
How would the mass of a potato cylinder change if you put it in a solution that has the same water concentration as the fluid inside the potato
There would be no change in mass of the potato cylinder
Yas has two potato cylinders. The fluid inside the potato cells has the same concentration. She weighss the two cylinders and places them into different beakers one of pure water the other with glucose solution. after 24 hours she removed the cylinders, dries them and measures their final mass. Explain how the mass of each potato cylinder will have changed after 24 hours.
The mass of the cylinder in pure water will have increased because the water will have moved by osmosis from an area of higher water concentrate in the pure water to an area of lower concentration in the potato. the mass of the cylinder in the glucose solution will have decreased as the water will have moved by osmosis from the area of higher water concentration in the potato to an area of low concentration, the glucose solution
If during an experiment of investigating the water movement by osmosis, the potato cylinders weren’t dried properly, so the excess water added to the mass of the potato was added how could this error be reduced?
Repeat the experiment and calculate the mean percentage change in mass
