Unit 1 Flashcards
Name the 4 bases in DNA
Adenine, guanine, thymine, cytosine
How are the bases paired
(A,T) (C,G)
What is the shape of a DNA molecule
DNA molecule consists of 2 strands that wind around one another to form a shape as a double helix
What are nucleotides in a chain joined together by
Sugar-phosphate bond
Why are nucleotides in a chain joined together by a sugar-phosphate bond
To make long chains of nucleotides- called polynucleotides
What are polynucleotides joined together to the bases with
Hydrogen bonds
Why is the double helix described as having two anti-parallel chains of nucleotides
One side goes from 5’ to 3’ and the opposite side goes from 3’ to 5’
What is DNA composed by
Two polynucleotide chains
What does nucleotides consist of
A sugar-phosphate and base
Why do nucleotides bond
To form a sugar-phosphate back bone
What are the nucleic acid bases paired by
Hydrogen bonding in the centre to form a double helix
What does a nucleus of a cell contain
Chromosomes, which are composed of genes made of DNA
What does DNA Carry
Genetic info for making protein
What Is required in a polymerase chain reaction (PCR)
DNA polymerase, template strand and prime
Stage of aerobic respiration, it’s site and an event which occurs during that stage
Citric acid cycle, matrix of mitochondrion, carbon dioxide is released
Name the molecules in an RNA nucleotide
deoxyribose in DNA attached to a phosphate group and a nitrogen-containing base.
Name the type of bond on the backbone of the RNA molecule
Phosphodiester bonds
Describe 3 differences between RNA and DNA molecules
RNA is single stranded while DNA is double stranded, RNA contains uracil while DNA contains thymine, RNA has the sugar ribose while DNA has the sugar deoxyribose
State what mRNA is and describe its role
mRNA is a single-stranded molecule that carries genetic code from DNA in a cell’s nucleus to ribosomes, the cell’s protein-making machinery.
State what tRNA is and describe its role
(tRNA) is a type of RNA molecule that helps decode a messenger RNA (mRNA) sequence into a protein
State the location of transcription
In the nucleus
Describe the process of transcription
Transcription is the process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).
What are metabolic pathways
Metabolic pathways are integrated and controlled pathways of enzyme catalysed reactions within a cell
What can metabolic pathways have
Reversible steps, irreversible steps and alternative routes
Reactions in metabolic pathways can be
Anabolic or catabolic
What do anabolic reactions do
They build up large molecules from smaller molecules and require energy
What do catabolic reactions do
They breakdown large molecules into smaller molecules and release energy
What are protein pores, pumps and enzymes embedded in
Membranes
What are metabolic pathways controlled by
The presence or absence of particular enzymes and the regulation of the rate of reaction of key enzymes
When does induced fit occur
When the active site changes shape to better fit the substrate after the substrate binds
What do competitive enzymes bind to
The active site
Why do competitive inhibitors bind to the active site
To prevent the substrate from binding
What is the cell membrane
It is the boundary that separates the internal contents of the cell from its external surroundings
What does the membrane do
The membrane regulates the flow of materials into and out the cell
What are cell organelles bounded by
Membranes
Meaning of catabolic pathways
Catabolic pathways are those that generate energy by breaking down larger molecules.
The meaning of anabolic pathways
Anabolic pathways are those that require energy to synthesize larger molecules.
Give example of catabolic reactions
An example of a catabolic reaction is the process of food digestion
Example of anabolic reactions
An example of an anabolic reaction is the synthesis of glycogen from glucose
Give example of a metabolic reactions which is reversible
Glycolysis results in the breakdown of glucose, but several reactions in the glycolysis pathway are reversible and participate in the re-synthesis of glucose
Give an example of an alternative route for a metabolic pathway
Sorbitol
What do membranes form surfaces and compartments for metabolic pathways
To localise metabolism
Describe the functions of membrane proteins to include protein pores, pumps and enzymes
Transport proteins, enzymes, receptors, recognition proteins and joining proteins.
Why enzymes speed up chemical reactions by lowering the activation energy
Enzymes generally lower activation energy by reducing the energy needed for reactants to come together and react.
Why the induced fit model of enzyme action in terms of enzyme shape and binding the active site
The induced fit model states an substrate binds to an active site and both change shape slightly, creating an ideal fit for catalysis.
What’s the effect of increasing substrate concentration on enzyme activity
an increase in substrate concentration leads to an increase in the rate of an enzyme-catalyzed reaction.
What’s the effect of increasing end product concentration on the rate of enzyme reaction
increase the rate of the reaction.
What’s an example of enzymes that work in groups or multi enzyme complexes
the pyruvate dehydrogenase complex (PDC)
State that enzymes activity can be controlled by inhibitors
By binding to enzymes’ active sites, inhibitors reduce the compatibility of substrate and enzyme and this leads to the inhibition of Enzyme-Substrate complexes
What is competitive inhibitors
The competitive inhibitor binds to the active site and prevents the substrate from binding there
What is non competitive inhibitors
The noncompetitive inhibitor binds to a different site on the enzyme
What is respiration
the act or process of breathing : the inhaling of oxygen and the exhaling of carbon dioxide. 2 :the process by which cells use oxygen to break down sugar and obtain energy
The rate of respiration is
Higher with glucose than with lactose
