cell biology Flashcards
what is the function of the cytoplasm
site of cell reactions
what is the function of the cell membrane
controls entry and exit of molecules to cells
what is the function of the nucleus
controls cell activities (contains genetic information)
what is the function of the ribosomes
site of protein synthesis
what is the function of the mitochondria
site of aerobic respiration
what is the function of the cell wall
gives the cell support and structure
what is the function of the vacuole
contains cell sap
what is the function of the chloroplasts
contains chlorophyll. Traps light for photosynthesis
what is the function of the plasmid
additional rings of DNA
what is the structure of the membrane?
It is made up of proteins and phospholipids. It has a selectively permeable membrane which small molecules like glucose water and oxygen can pass through but larger molecules like starch and fat cannot
describe diffusion
diffusion is a form of passive transport. Movement from high concentration to low concentration down a concentration gradient. No energy is required.
What is osmosis?
Osmosis is the diffusion of water molecules from a region of high water concentration to a region of lower water concentration through a selectively permeable membrane. Osmosis is a passive process, it does not require energy.
what is active transport?
ions/ molecules move from low to high concentration against a concentration gradient. Energy is required, this is an active process.
what is a chromosome?
The nucleus of the cell carries genetic information in structures called chromosomes - chromosomes contain DNA
what is a gene?
a gene is a section of DNA which codes for making protein to give you a characteristic.
describe the structure of DNA
- DNA is a double stranded helix held together by complimentary base pairs
- DNA carries the genetic information for making proteins
- ATGC
what are proteins made up of?
proteins are made up of many subunits called amino acids linked together in long chains by peptide bonds
how are proteins different from eachother?
each proteins has its own sequence of amino acids. The sequence of amino acids determines the structure and function of the protein.
- the DNA base sequence determines the amino acid sequence in proteins
what is messenger RNA?
mRNA is a molecule which carries a complimentary copy of the genetic code from the DNA in the nucleus to a ribosome where the protein is assembled from amino acids
what is the cell wall made of?
the cell wall is made of cellulose fibres, it keeps the cell rigid. It resists the uptake of water to maintain the shape and support of the cell. Fungal and bacterial cell walls are not made up of cellulose fibres but do the same job.
what are the functions of protein?
antibodies, structural, enzymes, hormones, receptors
which molecules are found in the cell membrane and move ions by active transport?
protein molecules
why is diffusion important to cells?
diffusion is important to cells and multi cellular animals because cells require glucose and oxygen to diffuse into them so they can release energy during aerobic respiration. During this respiration process cells make the waste product, carbon dioxide which must diffuse out of the cells so they can stay alive.
effect of osmosis on plant cells
plasmolysed
stay same
turgid
plasmolysed means when there’s low water the cell shrinks
turgid means when theres too much water the cell swells
how is mRNA produced?
- the genetic code is copied to produce a messenger RNA
- messenger RNA carries a complementary copy of the genetic code from the DNA out of the nucleus to a ribosome in the cytoplasm
- amino acids arrive at the ribosomes and line up according to the sequence of bases on the mRNA
- peptide bonds form between the amino acids. This forms a protein molecule.
what are enzymes?
enzymes are proteins which are biological catalysts made by all living cells. They speed up chemical reactions and are unchanged in the process
what is the purpose of a control experiment?
control experiments are set up to ensure that any change in results are due to the variable that is altered. They have to be identical to the original experiment minus the altered variable.
what is a substrate?
A substrate is the molecule on which the enzyme works
what happens during an enzyme controlled reaction?
during an enzyme controlled reaction the molecule on which the enzyme works called the substrate joins temporarily onto the active site on the surface of the enzyme. This speeds up the chemical reaction and forms the product(s)
an enzyme substrate complex is formed
why are enzymes specific?
Enzymes are said to be specific to a particular substrate because the shape of the active site of an enzyme molecule is complementary to it’s specific substrate
what is a degredation reaction?
a reaction in which large complex molecules are broken down into smaller simpler ones
what is a synthesis reaction?
A reaction in which small simple molecules are built up into larger more complex ones
PROBLEM SOLVING AND OTHER
- energy pyramids and stuff
- cell microscope thing
- percentage change
- percentage
- ratios
- look at the diagram of genetic engineering
what colour is iodine if starch is present?
blue/ black, if it’s not present it’s brown
when are enzymes most active?
when they are in their optimum conditions.
which two factors can affect enzymes and proteins?
pH and temperature
what happens to an enzyme when it’s not at its optimum pH?
Above and below an enzymes optimum pH the enzyme is denatured, therefore it’s activity is reduced
what is genetic engineering?
genetic engineering is when genetic information can be transferred from one cell to another
what are the steps involved in the genetic engineering process?
- identify the section of DNA that contains required gene from source chromosome
- extract required gene
- extract plasmid from bacterial cell and insert required gene into bacterial plasmid
- insert plasmid into another host bacterial cell to produce a genetically modified organism
- genetically modified bacterial cell divides and produces the required product.
which steps in the genetic engineering process involve enzymes?
- cutting human DNA to extract the required gene
- cutting open the plasmid
- sealing the human gene into the bacterial plasmid
