Key concepts in Biology Flashcards
What is a Cell?
The smallest, basic unit of life that is responsible for all life’s processes.
What are Animal and Plant cells called?
Eukaryotic cells
What is in a Eukaryotic cell?
Cell membrane, Cytoplasm and a Nucleus containing DNA.
What are Bacterial cells called?
Prokaryotic cells.
What is in a Prokaryotic cell?
Cell wall, Cell membrane, cytoplasm and Singular strand of DNA and Plasmids.
What is the function of a Nucleus?
Contains genetic material that controls the activities of the cell.
What is the function of the Cytoplasm?
Where most of the chemical reactions happen. It contains Enzymes which control these chemical reactions.
What is the function of the Cell membrane?
Holds the cell together and controls what enters and exits the cell.
What is the function of the Mitochondria?
These are where most of the reactions for respiration take place. Respiration transfers energy that the cell needs to work.
What is the function of the Ribosomes?
Involved in 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?
Contains cell sap, store food or any variety of nutrients a cell might need to survive.
What is the function of the Chloroplasts?
Where photosynthesis occurs, contain a green substance called chlorophyll.
What is the function of Chromosomal Dna (one long circular chromosome) in the Bacterial cell?
Controls cell’s activities and replication. Floats free in the cytoplasm.
What is the function of the Plasmid DNA?
Small loops of extra DNA that aren’t part of the chromosome. contains genes for things like drug resistance.
What is the function of the Flagellum?
Long, hair like structure that rotates to make the bacterium move, used to move bacteria away from harmful substances.
What is a Specialised cell?
A cell which has a specific function.
What are the 2 cells which are specialised for reproduction?
Egg cells and Sperm cells.
What happens in sexual reproduction?
The nucleus of an egg cell fuses with the nucleus of a sperm cell to create a fertilised egg, which then develops into an embryo.
What is the function of an Egg cell?
Contains nutrients in the cytoplasm to feed the embryo
has a haploid nucleus
after fertilisation, its membrane changes structure to stop any sperm getting in. This is to end up with the right amount of DNA.
What are the functions of the Sperm cell?
To transport the males DNA to the female’s egg.
Name the Key features of a Sperm cell.
Long tail so it can swim
lots of mitochondria to provide energy
an acrosome where it stores enzymes needed to digest its way through the membrane of the egg
contains a haploid nucleus.
What is the function of the Ciliated Epithelial Cell?
To move substances in one direction, along the surface of the tissue.
What is the function of the Enzyme?
Reduce the need for high temperatures and we only have enzymes to speed up the useful chemical reactions in the body.
What is the Substrate?
The molecule changed in the reaction.
What does every Enzyme have?
An active site, part where it joins on to its substrate to catalyse the reaction.
What is needed for the enzyme to work?
The substrate has to fit into the active site.
What affects the Rate of Reaction?
Temperature, pH and Substrate concentration.
What happens if the temperature gets TOO hot?
Some of the bonds holding the enzyme together break.
How does pH affect the Enzymes?
If too high or too low, it interferes with bonds holding Enzyme together. This changes the shape of the active site and denatures the enzyme.
How does Substrate Concentration affect the Enzyme?
Once all active sites are full, adding more makes no difference.
What do Enzymes called Carbohydrase do?
Convert carbohydrates into simple sugars.
What do Enzymes called Proteases do?
Convert proteins into amino acids
What do Enzymes called Lipases do?
Convert lipids into glycerol and fatty acids
How can Carbohydrates be synthesised?
Joining together simple sugars
How can Proteins be synthesised?
Joining amino acids together
What do Microscopes do?
Uses lenses to magnify images. they also increase the resolution of an image.
What is Resolution?
Means how well a microscope distinguishes between 2 points that are close together. Higher resolution = Image can be seen more clearly and in more detail.
what is a light microscope?
They work by passing light through the specimen. let us see things like nuclei and chloroplasts and we can also use them to study living cells.
what is an electron microscope?
Use electrons rather than light. they have a higher magnification and resolution than light microscopes, so they let us see much smaller things in more detail like the internal structure of mitochondria and chloroplasts.
How do you work out the total magnification of an image?
Total magnification = eyepiece lens x objective lens magnification
What formula would you use to work out the magnification of an image if you didnt know which lenses were used?
Magnification = image size/real size
What is diffusion?
The net (overall) movement of particles from an area of higher concentration to an area of lower concentration
In what states of matter does diffusion occur?
Both liquids and gases because the particles in these substances are free to move about randomly.
What is osmosis?
The net movement of water molecules across a partially permeable membrane from a region of higher water concentration to a region of lower water concentration.
what is a partially permeable membrane?
One with very small holes in it. so small only tiny molecules can pass through them.
What is Active Transport?
The movement of particles across a membrane against a concentration gradient using energy transferred during respiration
