Topic 1 - Key Concepts In Biology Flashcards
What are eukaryotic cells?
Cells that have a nucleus. They are more complex and include all animal and plant cells.
What are prokaryotic cells?
Cells that have no nucleus. These are smaller and simpler cells.
What is the function of a nucleus?
It contains the genetic material that controls the activities of the cell. Genetic material is arranged into chromosomes.
What is the function of the cytoplasm?
A gel-like substance where most of the chemical reactions happen. It contains enzymes that control these chemical reactions.
What is the function of the cell membrane?
Holds the cell together and controls what goes in and out.
What is the function of the mitochondria?
These are where most of the reactions for respiration take place. Respirations transfers energy that the cell needs to work.
What is the functions of the ribosomes?
These are involved in the translation of genetic material in the synthesis of proteins.
What is the function of the cell wall?
Made of cellulose. It supports the cell and strengthens it.
What is the function of the vacuole?
It contains sap and is a weak solution of sugar and salts. It maintains the internal pressure to support the cell wall.
What is the function of the chloroplasts?
These are where photosynthesis occurs, which makes food for the plant. They contain a green substance called chlorophyll.
What is the function of the chromosomal DNA?
It’s like one, long circular chromosome. It controls the cell’s activities and replication. It floats free in the cytoplasm not nucleus.
What is the function of the plasmid DNA?
Small loops of extra DNA that aren’t part of the chromosome. Plasmids contain genes for things like drug resistance, and can be passed between bacteria.
What is the function of the flagellum?
A long, hair-like structure that rotates to make the bacteria move. It can be used to move the bacteria away from harmful substances like toxins and towards beneficial things like nutrients to oxygen.
What is a multicellular organism?
An organism that contains lots of different types of cells (i.e. cells with different structures).
What is a specialised cell?
Cells that have a structure which makes them adapted to their functions.
What is a haploid cell?
A cell that only has a single set of unpaired chromosomes.
What are the main functions of the egg cell?
To carry the female DNA and nourish the developing embryo in early stages.
What are the 3 ways in which an egg cell is adapted to its functions?
1) It contains nutrients in the cytoplasm to feed the embryo.
2) It has a haploid nucleus.
3) Straight after fertilisation, its membrane changes structures to stop any more sperm getting in. This makes sure the offspring end up with the right amount of DNA.
What is the function of the sperm cell?
To transport the male’s DNA to the female’s egg.
What are the 4 ways in which a sperm cell is adapted to its function.
1) A sperm cell has a long tail so it can swim to the egg.
2) It has lots of mitochondria in the middle section to provide the energy (from respiration) needed to swim this distance.
3) It also has an acrosome at the front of the ‘head’, where it stores enzymes needed to digest its way through the membrane of the egg.
4) It also contains a haploid nucleus.
What is the function of a ciliated epithelial cell?
Moving materials.
What are the 4 ways in which a ciliated epithelial cell is adapted to its function?
1) Epithelial cells line the surface of organs.
2) Some of them have cilia on the top surface of the cell.
3) The function of the ciliated epithelial cells is to move substances - the cilia beat to move substances in one direction, along the surface of the tissue.
4) For example, the lining of the airways contains lots of ciliated epithelial cells. These help move the mucus (and all of the particles from the air that it has trapped) up to the throat so it can be swallowed and doesn’t reach the lungs.
What is the use of a lens in a microscope?
Magnify images.
What is the resolution of a microscope?
How well a microscope distinguishes between two points that are close together.
What does a higher resolution mean?
An image can be seen in more detail and more clearly.
How do light microscopes work?
They work by passing light through the specimen. They let us see things like nuclei and chloroplasts and we can use them to study living cells.
How do electron microscopes work?
They use electron rather then light and have a higher resolution and magnification than light microscopes. Therefore they let us view much smaller things in more detail like the internal structure of mitochondria and chloroplasts. However they can’t be used to view living cells.
What is the formula to work out total magnification?
Total magnification = Eyepiece lens magnification X Objective lens magnification.