S5 - Unit Two Flashcards
What does the term metabolism mean?
All chemical reactions that occur within a living cell
What are metabolic pathways?
Pathways that are integrated and controlled by enzyme-catalysed reactions within a cell
What names can be given to reactions within metabolic pathways?
Catabolic or Anabolic reactions
What is the definition of a catabolic reaction?
The break down of large molecules into smaller molecules which releases energy
What is an example of a learned about catabolic reaction?
Respiration
What is the definition for an anabolic reaction?
The build up of large molecules from smaller molecules which requires energy
What is an example of a learned about anabolic reaction?
Protein synthesis
What type of steps can occur in a metabolic pathway?
- Reversible
- Irreversible
- Alternative routes
Why do metabolic pathways have different types of steps?
To allow them to be kept under precise control
What does a cell membrane consist of?
Protein pores, pumps and enzymes
What is the use of the following in a cell membrane?
- Pores
- Pumps
- Enzymes
- Used in diffusion
- Used for active transport
- Used to speed up the rate of a chemical reaction
What are metabolic pathways controlled by?
The presence of absence of particular enzymes and the regulation rate of reaction of key enzymes
What is the activation energy?
The energy required to break the bonds between reactant molecules
What do enzymes do to the activation energy?
Lower it
What is induced fit?
When the active site of an enzyme changes shape to better fit a substrate after it binds
What does affinity mean?
The chemical attraction molecules have for each other
What factors affect the rate of reaction?
The substrate concentration, temp. and concentration
What happens at a low substrate conc. to the rate of reaction and why?
It decreases as not enough substrate molecules are present to fill the active site
What happens at a high substrate conc. to the rate of reaction and why?
It increases as more active sites are filled
When does the rate of reaction when substrates bind to enzymes stop increasing?
When all the active sites have been filled
Why do we have inhibitors?
To regulate the action of a metabolic pathways enzymes
What is an inhibitor?
A substrate which decreases the rate of an enzyme controlled reaction
What types of inhibitors are there?
Non-competitive and competitive
How do competitive inhibitors affect an enzyme and its rate?
By binding to the enzymes active site due to it having a similar shape to the substrate, preventing the substrate from binding
How can competitive inhibitors be reversed and why is this?
By increasing the substrate conc.
Because the substrate molecules outnumber the inhibitors
How do non-competitive inhibitors affect an enzyme and its rate?
By binding away from the active site but changing the shape of the active site preventing a substrate from binding
When does feedback inhibition occur?
When the end product in the metabolic pathway reaches a critical conc.
How does feedback inhibition work and what does it do?
An end product inhibits an earlier enzyme, blocking the pathway and therefore preventing further synthesis of the end product
What is ATP used for?
To transfer energy to cellular processes that require energy
What is phosphorylation and what is a common example in Higher?
An enzyme controlled process by which a phosphate group is added to a molecule
ADP + Pi = ATP
What happens if ATP is used to phosphorylate another molecule?
The molecules becomes more reactive
What are the stages in aerobic respiration?
- Glycolysis
- Citric Acid Cycle
- Electron Transport Chain
Where do each of the stages in aerobic respiration take place?
- Cytoplasm
- The matrix of the mitochondria
- The inner membrane of the mitochondria
Name the stage of aerobic respiration and the missing words.
What is glycolysis?
The breakdown of glucose to pyruvate in the cytoplasm
Why is ATP needed in the first phase of glycolysis?
To phosphorylate glucose and intermediates
What does the phosphorylation of glucose and intermediates in phase one of glycolysis lead to?
The generation of more ATP in the second phase, resulting in a net gain of ATP
What do dehydrogenase enzymes do in glycolysis?
Remove hydrogen ions and electrons, passing them to the enzyme NAD which then forms NADH
Name the stage of aerobic respiration and the missing words
What does the enzyme NAD do in the second stage of aerobic respiration?
Becomes NADH and passes the hydrogen ions and electrons to the third and final stage
Name the stage of aerobic respiration and the missing words
What happens in aerobic respiration when no oxygen is present?
Fermentation takes place
Name the cell the fermentation is occurring in and the missing words
Where does fermentation take place?
The cytoplasm
What is metabolic rate?
The quantity of energy consumed by an organism per unit time
What are the different ways metabolic rate can be measure as?
- Oxygen consumption (per unit time)
- Carbon dioxide production ‘’
- Heat production ‘’
What are the abiotic factors learned about at Higher?
- temp.
- pH
- salinity (saltiness)
What is a conformer?
When the internal environment of an organism is directly dependant on the abiotic factors that affect external factors
What is an advantage to being a conformer?
Metabolic costs are low as they do not use metabolism to control their internal environment
What is a disadvantage to being a conformer?
They are restricted to a narrow ecological niche
What are regulators?
Organisms that maintain their internal environment regardless of their external environment by using their metabolism
What is an advantage of being a regulator?
Can occupy a greater range of ecological niches
What is a disadvantage to being a regulator?
Metabolic costs are high to achieve homeostasis
How is homeostasis maintained?
Through negative feedback control
What is negative feedback control?
Feedback which provides the body with stable conditions to function properly
What is thermoregulation?
A process by which mammals maintain their body temp at a constant 37 degrees
What is the hypothalamus?
The body’s temp. monitoring centre in the brain
What does the hypothalamus do to monitor the body’s temp?
Communicates info through electrical impulses through nerves to effectors which then bring about the corrective response
What does the body do to correct an increase in body temp?
- Dilates blood vessels
- Increases sweating
- Decreases metabolic rate
What are things the body does to correct a decrease in body temp?
- Dilation of blood vessels
- Hair erector muscles contract
- Increased metabolic rate
Why is it important to regulate body temp?
For optimal enzyme activity and for high diffusion rates to maintain metabolism
What are adverse conditions?
Conditions that vary beyond the tolerable limits for normal metabolic activity for any particular organism
What do organisms do to survive adverse conditions?
Reduce metabolic rate and have periods of dormancy during periods where the cost of continued normal metabolic activity would be too high
What happens to an organism during dormancy?
Their metabolic, heart and breathing rate and their body temp decrease
What are the two types of dormancy?
Predictive and consequential
What is predictive dormancy?
When an organism becomes dormant before the onset of the adverse condition
What is consequential dormancy?
When an organism becomes dormant after the onset of the adverse condition
What is hibernation?
A form of dormancy where an organisms metabolic rate is reduced when temps. are low and food is scarce
What is aestivation?
A form of dormancy where an organisms metabolic rate remains at a minimum to survive high temperatures and drought
What is daily torpor?
A period of reduced activity in some animals with high metabolic rates
What is migration?
A way of avoiding metabolic adversity by expending energy to relocate to a more stable environment
What are methods in which migration can be studied?
For birds: leg ringing and recovery
For turtles: satellite tracking
What are the different forms of migratory behaviour?
Innate and learned
What do each of the forms of migratory behaviours mean for an organism?
Innate: It is inherited and inflexible
Learned: It begins after birth and is influenced by an organisms experiences
What are reasons we use microorganisms in industry?
Because they can make a wide variety of substrates for metabolism and they produce a range of products from their metabolic pathways
Because of their adaptability, ease of cultivation and speed of growth
What does the term “microorganism” talk about?
- Archaea
- Bacteria
- (some species of) Eukaryotes
Why are microorganisms used in industry?
They make a wide range of metabolic products
What are environmental factors required for the growth of microorganisms?
Optimum pH, temp. and oxygen conc.
What are the growth mediums that are required for the growth of microorganisms?
An energy source and raw materials
What do sterile conditions in fermentors do?
Reduce competition with desired microorganism for nutrients and reduce the risk of spoilage of the product
What is the mean generation or doubling time of an microorganism?
The time taken for a cell to divide into two
What are the 4 phases of cell growth and identify them on the graph
What happens in the first stage of cell growth?
Enzymes are induced to metabolise new substrates
What happens in the second stage of cell growth?
There is a rapid growth of microorganisms due to plentiful nutrients
What happens in the third stage of cell growth?
Nutrients deplete and toxic metabolites are produced
Secondary metabolites are produced and confer an ecological advantage in the wild as they allow microorganisms which produce them to outcompete other microorganisms
What happens in the final stage of cell growth?
There is an accumilation of toxic metabolites and lack of nutrients in the culture
Identify each component of the fermenter and what it’s purpose it
What are the names given to the different types of cell counts?
- Viable cell count
- Total cell count
How can you tell the two types of cell counts apart?
Only viable cell counts show a death phase on a graph
What is a viable cell count?
When only the living cells are counted
What is a total cell count?
When living and dead cells are counted
What two techniques can be used to improve wild strains of microorganisms for industrial processes?
Mutagenesis and recombinant DNA technology
What is mutagenesis?
The creation of a mutation
Why do we use mutagenesis?
As it allows more opportunities to develop new properties in microorganisms that are useful to humans
What is recombinant DNA technology?
When scientists transfer genes from one organism to another or even from one species to another
What does recombinant DNA technology allow to happen?
Microorganisms to produce plant or animal cells
What term is used to describe a microorganisms that has undergone recombinant DNA technology?
Artificially transformed
What is a vector in Biology?
A DNA molecule used to carry foreign genetic material into another cell
What are examples of vectors in recombinant DNA technology?
Plasmids and artificial chromosomes
When are artificial chromosomes more preferable to plasmids as vectors in recombinant DNA technology?
When larger fragments of foreign DNA are required to be inserted
What is restricting endonuclease?
An enzyme which cuts target sequences of DNA and leaves sticky ends
What are sticky ends in Biology?
Unpaired bases
What is restricting endonuclease used for?
- Cutting specific genes out of a chromosome
- Cutting open bacterial plasmids
What is ligase able to do in recombinant DNA replication?
Seal the gene into the plasmid
What makes an effective vector?
A plasmid with a restriction site, selectable markers, origin of replication and regulatory sequences
What is the restriction site of a plasmid?
A section which contains target sequences of DNA where specific restriction endonuclease cuts
What are selectable marker genes of a plasmid?
Genes that protect the microorganism from a selective agent that would normally kill it or prevent it growing
What is an example of a selectable marker gene and a selective agent?
- Antibiotic resistant genes
- Antibiotics
What is the origin of replication of a plasmid?
A section which allows self replication of the plasmid/artificial chromosome
Why are origins of replication so important?
Because they are essential for making many copies of the plasmid and the required gene. These can be passed on to the daughter cell.
What are the regulatory sequences of a plasmid?
A section which controls gene expression
What is a control in an experiment?
An element of an experiment that remains unchanged or unaffected by other variables
What is an independent variable in an experiment?
A variable that is altered during an experiment
What is the dependant variable in an experiment?
The variable being measured
What might result in inactive proteins and why?
Plant or animal DNA being expressed in bacteria due to incorrect folding
How can inactive proteins be fixed?
Swapping the bacteria cell with a yeast cell to allow the DNA to be folded correctly
What are ethical considerations in the use of microorganisms?
The hazards that could occur and how to control them.
Being aware of potential mutations which could result in pathogens or their scape into the wild environment.
