B1 Flashcards
(54 cards)
Definition of a eukaryotic and prokaryotic cell
Eukaryotic- complex cell which contain their genetic material in a nucleus
Prokaryotic cell- simpler cell which don’t contain their genetic material in a nucleus
Function of the ribosomes
The ribosomes are the site of protein synthesis
Functions of the mitochondria
Mitochondria are the site of respiration and contain the enzymes needed
Function of the vacuole
The vacuole is filled with cell sap which helps the cell to keep its shape
What stain stains cytoplasm?
Eosin stains cytoplasm
Which stain stains DNA?
Methylene blue stains DNA
What is the difference between lights and electron microscopes
Invented in the 1590’s light microscopes have limited resolution so can only see internal structures of cells
Invented in the 1950’s electron microscopes have a much higher resolution and magnification so can see internal structures of mitochondria and plasmids
Disadvantages of the electron microscope
The electron microscope is expensive, not portable and difficult to set up and prepare a sample do living tissue cannot be used
Magnification=
Magnification= image size/ real size
What are the monomers called that make up DNA?
DNA is made up of Nucleotides
Explain the structure of nucleotides
Nucleotides are made up of left to right: phosphate, sugar and a base
Which bases pair complementary?
A and T
C and G
What type of structure does DNA have?
A double helix structure
What do each gene code for?
And what is this substance made from?
What are the things it is made from coded by?
Each gene codes for a protein which is made up of amino acids which are each coded for by three bases
Explain the stages of protein synthesis
Good luck 😊
TIP REMEMBER THE TWO MAIN STAGES NAMES (starts with t)
1) TRANSCRIPTION The enzyme RNA causes the DNA in the nucleus to unzip. mRNA is then formed using the DNA as a template to create a chain of the complementary opposite bases
2) When the section for the protein is copied the mRNA will leave the nucleus
3) In the cytoplasm the mRNA attaches to a ribosome
4) TRANSLATION tRNA carrier molecules bring amino acids to the ribosomes they read the triplet codes of bases to determine the right order for the amino acids
5) The amino acids are joined by peptide bonds as the tRNA leaves
6) When the sequence had been completed the chain of amino acids leaves and folds into a complex shape which determines the function of the protein
What are enzymes?
Enzymes are biological catalysts which speed up a reaction without being used up
Why do organisms produce enzymes to speed up reactions rather than just increasing the temperature?
Because increasing the temperature would not only speed up desired reactions it would also speed up unwanted ones which could be dangerous for an organism
What is the ‘lock and key hypothesis’?
Each enzyme has an active site specifically designed to fit a particular substrate. This means enzymes have a high specificity for their substrate
How does increasing temperature, Ph, enzyme concentration and substrate concentration affect reaction rate?
Temperature will increase reaction rate up until a point because it increased movement meaning enzymes are more likely to meet with substrates and react. However if the temperature gets too high the enzyme gets denatured the and the active site loses its shape so the substrate doesn’t fit and a reaction cannot take place. Every enzyme has an optimum temperature
Ph- every enzyme has an optimum Ph if the Ph gets too high or too low the enzyme is denatured also
Enzyme concentration- the more enzymes the more likely it is they will meet with a substrate and react so rate of reaction increases. However once all substrates are reacting adding enzymes won’t have any effect so
reaction rate stops increasing and is steady
Substrate concentration- the more substrates the more likely it is that they will meet with an enzyme and react however when all active sites are full adding substrates have no effect so rests if reaction stops increasing and is steady
Spain how to set up an experiment to investigate the effect of temperature, pH, enzyme or substrate concentration on enzyme activity
1) heat 2cm3 of amylase and starch solution in separate test tubes in a water bath to 30 degrees
2) mix and put back in the water bath
3) start the stopwatch
4) every 30 seconds take a sample and put in a spotting tile containing a drop of iodine
5) when the mixture remains orange /Brown and does not turn black stop the stopwatch
6) repeat varying the temperature to investigate temperature
Add a pH buffer solution at the beginning and vary the pH when you repeat to investigate pH
Vary concentration of amylase or starch for enzyme/ substrate concentration
What is respiration?
The transfer of energy due to the break down of glucose (or other organic molecules including carbohydrates proteins and lipids) are
State the equation and energy of aerobic respiration
Aerobic respiration
Glucose + oxygen —> carbon dioxide and water
C6H12O6 + 602—> 6CO2 + 6H2O
And produces 32 ATP
State the equation in plants and animals and energy produces for anaerobic respiration
Anaerobic respiration is:
Glucose—>lactic acid in animals
And produces 2ATP
Glucose—>ethanol +carbon dioxide in plants
Why does anaerobic respiration produce lactic acid in animals?
The glucose is only partially broken down in anaerobic respiration which creates lactic acid and muscle fatigue
