1. Key concepts in biology Flashcards
(26 cards)
State what is meant by active transport
movement of particle across a membrane AGAINST a concentration gradient using sufficient energy transferred during respiration. (particles move up a c.g =requires energy)
Explain the effect of concentration on a enzyme activity
The greater the substance concentration =greater the enzyme activity and the higher the rate or reaction.
EXPLANATION:as the number of substance molecules increases the formation of the enzyme-substance complex increases if enzyme concentration remains fixed but the amount of substrate is increased past a certain point active site becomes SATURATED.
Explain the effects of temperature on enzyme activity
As we increase the temperature =the activity of the enzyme increases
EXPLANATION:as the temp increases,the enzyme and substrate are moving FASTER so there are more collisions per second between the substrate and the active site.
Eukaryotes
Found in all animal and plant cells and are organisms made up of eukaryotic cells and contains a nucleus
Light & Electron Microscope
Light Microscope allows us to see plants and animal cells as separate objects however we still could NOT tell lots of sub-cellular structures apart
Electron microscope first used in 1933 electrons are passed through the specimen INSTEAD of light
What are the similarities of a Plant and Animal cell?
Nucleus-contains dan and controls activities of the cell.
Cytoplasm-gel like substance where chemical reactions happen
Cell membrane-holds the cell together and controls what goes in and out for the cell
Mitochondria-respiration takes place
Ribosome- responsible for making protein
What does Plant Cells have that animal cells do not have?
Rigid cell wall-supports cell and strengths made of cellulose
Large Vacuole-contains cell sap
Chlororplasts-where photosynthetis takes place
What is a Eukaryote and Prokayrote and examples?
Pro has NO nucleus eg. Bacterial cell, Euk HAS nucleus eg. Plant and Animal cell
What do bacterial cells not have?
Nucleus
What do Bacterial cells contain?
Chromosomal DNA-one long circular chromosome and controls the cells activity and replication,floats in the cytoplasm not in a nucleus
Ribosomes,responsible for making protein
Cell membrane, controls what exits and leaves the cell
Plasmid DNA-small loops of extra DNA that aren’t part of the chromosome contains genes for drug resistance and can be passed between bacteria
Flagellum, long hair-like structure that rotates to make bacterium move used to move bacteria away from harmful substances like toxins and towards beneficial things such as nutrients and and oxygen
What is a specialised cell?
A cells that have a particular function
In Sexual reproduction what does the nucleus of an egg cell fuse with and what does it create?
Creates a nucleus sperm cell which creates a fertilised egg which then develops into a embryo
What are haploids and what cells contain it?
A haploid is half the number of chromosomes that’s in a normal body cell and only contains the nucleus of an egg cell and a nucleus of an sperm cell
What is the main function of an egg cell?
Is to carry the female DNA and to nourish the developing embryo in the early stages
How has an egg cell been adapted to its function?
Contains nutrients in the cytoplasm to feed the embryo
It has a haploid nucleus
After fertilisation it’s membrane changes structure to stop any sperm cell getting in. This makes sure that the offspring ends up with right amount of DNA
What is the function of a sperm cell?
Transport the makes DNA to the female egg
What are the adaptations of an Sperm Cell?
Has a long tail so it can swim to the egg
Lots of mitrorchondria in the middle for energy(from respiration) 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.
It also contains a haploid nucleus
What is the function of a sperm cell?(1 mark)
To transport the male’s DNA to the female egg
Explain two ways in which sperm cells are adapted for this function?(4 marks)
Long tail to swim to cell
Lots of mitrocondhria to provide energy from respiration needed to swim this distance
Describe the function of these subcellular structures a) nucleus b) mitochondria c) ribosomes
Nucleus contains genetic material and controls the activites of the cell
Mitochondria where respiration takes place
Ribosomes-responsible for making protein
What is a higher resolution?
What does every enzyme have?
They have a active site
What does changing the temperuare change of an enzyme-catalysed reaction?
A higher temperature increases the rate but if it becomes too hot some of the bonds holding the enzyme together breaks and changes the shape of the enzymes active site and the substrate no longer fits so it becomes denatured.
What is a catalyst?
Substance that increases the speed of a reaction without being used up
