Topic 1:5 - Cell metabolism Flashcards
features of mitochondria: outer membrane
It is a lipid bilayer membrane containing carrier and channel proteins as well as embedded enzymes (proteins) that catalyse chemical reactions in the cytoplasm.
features of mitochondria: inner membrane
lipid bilayer membrane contains channel proteins associated with the enzyme ATP synthase. It has extentions called cristae which increase it’s SA and hence the rate of ATP synthesis, since more enzymes and proteins are available for oxidative phosphorilation
features of mitochondria: matrix
The space enclosed by the inner mitochondrial membrane. The matrix contains mitochondrial DNA, ribosomes and enzymes that carry out important biochemical reactions.
features of mitochondria: inter membrane spaces
The space between the outer and inner membrane receives protons and other substances during the process of ATP synthesis to produce concentration gradients that then provide energy for ATP synthesis.
features of chloroplasts: the inner membrane and outer membrane
They Regulate transport of materials between the stroma and the cytoplasm of a plant cell.
The inner membrane contains enzymes that carry out the synthesis of some pigments and lipids.
features of chloroplasts: thylakoids
Membrane bound sacs containing light-absorbing pigments, like chlorophyll. Also contains channel proteins associated with the enzyme ATP synthase and enzymes that are involved in photosynthesis.
features of chloroplasts: grana
A granum (plural grana) is a stack of thylakoids. Grana increase the SA:V of light absorbing pigments which increases the rate of photosynthesis, and the number of sites for ATP synthesis.
features of chloroplasts: stroma
A gel-like fluid that contains enzymes which carry out chemical reactions in the process of photosynthesis.
features of chloroplasts: stromal lamellae
Extensions of the thylakoid membranes that increase the SA/V of light absorbing pigments which increases the rate of photosynthesis, the number of sites for ATP synthesis
what is a metabolic pathway?
The many regulated steps involved in a metabolic process, each requiring a specific enzyme.
An example of a metabolic pathway is glycolosis and oxidative phosphorylation.
What are four reasons for metabolic pathways
1.To reduce the activation energy of each step
- To allow reactions to occur at variable rates dependent on concentrations of substrate, product and enzymes, and presence of inhibitors.
- To ensure that the amount of heat released at each step is small, hence will not reduce the activity of enzymes in a cell.
- Intermediates produced part way through a catabolic metabolic pathway may be diverted to be used in an anabolic pathway or visa versa.
expand on this reason for many regulated steps: reduction of activation energy
*In metabolic pathways the activation energy required for each step is small.
*Enzymes increase the rate of metabolic reactions by reducing the activation energy of each step in the reaction.
expand on this reason for regulated steps: To allow reactions to occur at variable rates dependent on concentrations of substrate, product and enzymes, and presence of inhibitors.
Some enzymes in a pathway are regulatory enzymes and some of the intermediates in the pathway may inhibit a regulatory enzyme.
expand on this reason for regulated steps: To ensure that the amount of heat released at each step is small
Every step in a metabolic pathway releases some heat, hence if it is released in small steps it will not reduce the activity of enzymes in a cell.
expand on this reason for many regulated steps: Intermediates produced part way through a catabolic metabolic pathway may be diverted to be used in an anabolic pathway or visa versa.
A material produced in one metabolic pathway may be diverted to process differently in another pathway and ultimately produce a different product.
what are five environmental factors that affect metabolic pathways LAwTAseP
Light intensity
Availability of water
Temperature
Availability of substrates and enzymes
pH
Explain how temperature affects metabolism
The rates of enzyme-catalysed reactions increase until the optimum temperature is reached. The reaction rate decreases at higher temperatures as the enzyme becomes denatured.
explain how light intensity affects metabolism
The rate of the light-dependent reactions that are part of photosynthesis is affected by the intensity and wavelength of light being absorbed.
explain how pH affects metabolism
pH either side of the enzyme’s optimum alters the 3-Dshape (tertiary structure) of an enzyme’s active site which decreases the rate of the binding of the enzyme and substrate, hence the rate of an enzyme-catalysed reaction is decreased.
explain the effect of water availability on metabolism
Enzyme-catalysed reactions occur in the aqueous solution inside cells.
explain the effect of substrate and enzyme availability on metabolism
The rate of enzyme-catalysed reactions is dependent on both the substrate and enzyme concentration.
five examples of chemicals that interfere with metabolic pathways in cells are:
CHICA
-Chemotherapy drugs: interfere with and slow/stop the rapid division of cancer cells
-Herbicides: inhibit key enzymes in metabolic pathways needed for growth in plants
-Insecticides: interfere with metabolic pathways needed for growth in plants
-Co-factors: (inorganic substances like ions of zinc, iron and copper) and co-enzymes (organic molecules like vitammins) bind to an enzyme to complete the active sites required shape.
-Antibiotics: interfere with metabolism and stop cell wall production and hence reproduction of bacteria
What are the benefits of pesticides?
Kills pests which increase in crop yields and increases the health of humans, domestic animals and plants.
what are the harmful effects of using pesticides?
Pesticides that enter the human body can cause severe illness and be fatal. Reduction in insect populations can upset ecosystem balance.
what are the benefits of using fertilisers?
Increases crop yields hence provides suitable food sources to feed the human population.
what are the harmful affects of using fertilisers?
synthesised from fossil fuels, a non-renewable resource. Excess in run-off causes algal blooms.
What are the benefits of using Antibiotics?
Kills pathogenic bacteria that cause infectious diseases.
what are the harmful affects of using antibiotics?
Inappropriate and irresponsible use has given rise to antibiotic resistant superbugs that infect humans.
What are the benefits of using general pharmaceuticals?
Pharmaceuticals improve health, mood, well-being by treating illness caused by infectious and non-infectious diseases.
What are some harmful affects of using general pharmaceuticals?
Some pharmaceuticals are addictive. Drug addiction can have adverse effects on an individual, as well as their family, friends and community.
