Key Concepts In Biology Flashcards
What are eukaryotic cells?
Eukaryotic cells are complex and include all animal and plant cells. Eukaryotic cells contain nucleus.
What are prokaryotic cells?
Prokaryotic cells are smaller and simpler, e.g bacteria. A prokaryote is a single-celled organism.
What is in an animal cell?
- nucleus
- cytoplasm
- cell membrane
- mitochondria
- ribosomes
What is in a plant cell?
- nucleus
- cytoplasm
- cell membrane
- mitochondria
- ribosomes
- cell wall
- vacuole
- chloroplasts
What does the nucleus do?
Contains genetic material that controls the activities of the cell. Genetic material is arranged into chromosomes.
What does the cytoplasm do?
It is a gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions.
What does the cell membrane do?
Holds the cell together and controls what goes in and out.
What does the mitochondria do?
These are where most of the reactions for respiration take place. Respiration transfers energy that the cell needs to work.
What do the ribosomes do?
These are involved in translation of genetic material in the synthesis of proteins.
What does the cell wall do?
Cell wall is made up of cellulose. It supports the cell and strengthens it.
What does the vacuole do?
The vacuole contains cell sap, a weak solution of sugar and salt. It maintains the internal pressure to support the cell.
What do chloroplasts do?
These are where photosynthesis takes place, which makes food for the plant. They contain a green substance called chlorophyll.
What do bacterial cells contain?
- chromosomal DNA
- ribosomes
- plasmid DNA
- flagellum
What does the chromosomal DNA do?
Controls the cell’s activities and replication. It floats free in the cytoplasm.
What does the plasmid DNA do?
Plasmids contain genes for things like drug resistance, and can be passed between bacteria.
What is a flagellum?
A long, hair-like structure that rotates to make the bacterium move. It can be used to more the bacteria away from harmful substances like toxins and towards beneficial things like nutrients or oxygen.
What are egg cells and sperm cells specialised for?
Reproduction
What happens to egg cells and sperm cells in sexual reproduction?
The nucleus of an egg cells fuses with the nucleus of a sperm cell to create a fertilised egg, which then develop into an embryo. Both the nucleus of an egg cells fuses and of a sperm cell only contain half the number of chromosomes that’s in a normal body cell - so they are called ‘haploid’.
How is an egg cells fuses adapted to its function?
- it contains nutrients in the cytoplasm to feed the embryo.
- it has a haploid nucleus.
- straight after fertilisation, its membrane changes structure to stop any more sperm getting in. This makes sure the offspring end up with the right amount of DNA.
What is the main function of an egg cell?
To carry the female DNA and to nourish the developing embryo in the early stages.
What is the main function of a sperm cell?
To transport the male’s DNA to the female’s egg.
How is a sperm cell adapted to its function?
- long tail so it can swim to the egg
- contains lots of mitochondria in the middle section to provide the energy needed to swim this distance
- 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.
- contains a haploid nucleus
What is a ciliated epithelial cell?
- epithelial cells line the surface of organs
- some of them have cilia on the top surface of the cell
- they are specialised for moving materials
What is the function of a ciliated epithelial cells?
To move substances - the cilia beat to move substances in one direction, along the surface of the tissue. The lining of the airways contains lots of ciliated epithelial cells. These help to move mucus up to the throat so it can be swallowed and doesn’t reach the lungs.
