Topic 1. Key concepts in Biology. Flashcards
What is the function of the nucleus?
The nucleus contains genetic material that controls the activities of the cell.
Function of the cytoplasm?
The cytoplasm is a gel-like substance where most of the chemical reactions happen. It also contains enzymes that control these chemical reactions.
Function of the cell membrane?
It holds the cell together and controls what goes in or out.
Function of mitochondria?
These are where most of the reactions for respiration take place.
Function of ribosomes?
They are involved in translation of genetic material in the synthesis of proteins.
Function of the cell wall?
It is made of cellulose and supports the cell and strengthens it.
Function of the vacuole?
The vacuole contains cell sap, which is a weak solution of sugar and salts. It maintains the internal pressure to support the cell.
Function of chloroplasts?
These are where photosynthesis occurs, making food for the plant. They contain chlorophyll.
Function of chromosomal DNA?
It controls the cell’s activities and replication. It floats free in the cytoplasm.
Function of plasmid DNA?
Plasmids are extra loops of DNA that aren’t part of the chromosome. They contain genes for things like drug resistance and can be passed between bacteria.
Function of flagella?
A flagellum is a long, hair-like structure that rotates to make the bacterium move. It can be used to move the bacteria away from harmful substances like toxins and towards beneficial things like oxygen or nutrients.
Subcellular structures in an animal cell? (5)
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes
Subcellular structures in a plant cell? (6)
nucleus, cytoplasm, cell membrane, mitochondria, ribosomes, cell wall, vacuole, chloroplasts
Subcellular structures in a bacterial cell? (5)
chromosomal DNA, ribosomes, cell membrane, plasmid DNA, flagellum
How is an egg cell adapted to it’s function? (3)
It contains nutrients in the cytoplasm to feed the embryo.
It has a haploid nucleus.
Its membrane changes structure to stop any more soerm getting in straight after fertilisation. This makes sure the offspring end up with the right amount of DNA.
How is a sperm cell adapted to its function? (4)
A sperm cell has a long tail so it can swim to the egg.
It has lots of mitochondria in the middle section to provide the energy needed to swim the distance.
It has an acrosome at the front of the head, where it stores enzymes needed to digest its way through the membrane of the egg cell.
It contains a haploid nucleus.
What is the function of sperm cells?
To transport the male’s DNA to the female’s egg.
What is function of an egg cell?
To carry the female DNA and to nourish the developing embryo in the early stages.
Why do egg cells and sperm cells both have a haploid nucleus?
Because when an egg and sperm nucleus combine, the resulting cell with have the right no. of chromosomes.
What is the function of ciliated epithelial cells?
They move substances.
What are cilia?
Hair-like structures
What is the purpose of the ciliated epithelial cells that line the airways?
They move mucus and particles from the air up to the throat so it can be swallowed and doesn’t reach the lungs.
What does the term ‘haploid’ mean?
A cell containing half the no. of chromosomes that’s in a normal body cell.
Give an advantage of electron microscopes over light microscopes.
They have higher magnification and resolution.
Why is it necessary to use thin samples of tissue when viewing cells using a light microscope?
Because the specimen needs to let light through.
Why might you use a stain when viewing cells using a light microscope?
A stain may make the specimen easier to see and highlight certain structures within cells.
Which adjustment knob should you use first when using a light microscope?
Coarse adjustment knob
What is the equation you would use to find the size of a specimen using the magnification used and the size of the image seen through a microscope lens?
Real size = image size / magnification
How do you convert from mm to um?
Mm — um
x1000
Which unit can be expressed in standard form as 10-12m?
Picometre(pm)
Which unit can be expressed in standard form as 10-9m?
Nanometre(nm)
Which unit can be expressed in standard form as 10-6m?
Micrometre(um)
Which unit can be expressed in standard form as 10-3m?
Millimetre(mm)
What do carbohydrases do?
They convert carbohydrates into simple sugars.
What do proteases do?
Convert proteins into amino acids.
What do lipases do?
Convert lipids into glycerol and fatty acids.
