Essay Paragraphs Flashcards
(17 cards)
DNA replication
DNA helicase breaks hydrogen bonds between the complementary bases DNA strands separate and both DNA strands act as a templates
Free DNA nucleotides diffuse into position
According to complementary base pairing - Adenine with thymine and guanine with cytosine
DNA polymerase joins adjacent DNA nucleotides together using a condensation reaction To form phosphodiester bonds
Protein synthesis
DNA helicase breaks hydrogen bonds between the complementary bases DNA strands separate and one DNA strand acts as a template
Free RNA nucleotides diffuse into position
According to complementary base pairing Adenine with uracil and guanine with cytosine RNA polymerase joins adjacent RNA nucleotides together using a condensation reaction To form phosphodiester bonds
Pre-mRNA spliced to remove introns.
Mature mRNA contains exons and leave the nucleus via the nuclear pores
tRNA molecules bring amino acids to ribosome
Specific tRNA molecule for specific amino acid
Anticodon of tRNA is complementary to codon on mRNA
Two amino acids held close together on ribosome
Peptide bonds form between amino acids
tRNA detaches and collects another amino acid from cytoplasm Ribosome moves along mRNA
Light independent reaction
Light independent reaction fixes carbon dioxide
Carbon dioxide fixed to ribulose bisphosphate
The hydrolysed to make 2 molecules of glycerate-3-phosphate. The enzyme rubisco catalyses this reaction. Glycerate-3-phosphate becomes reduced.
to form 2 molecules of triose phosphate
Using NADPH from the light dependent reaction
Using ATP from the light dependent reaction
5/6 of the triose phosphate is converted into ribulose bisphosphate.
1/6 of the triose phosphate is converted into organic substances eg glucose.
Oxidative phosphorylation
Krebs cycle / link reaction produces reduced NAD and reduced FAD
NADH/FADH bind to the electron carrier proteins on inner mitochondrial membrane. Electrons released from NADH and FADH
Electrons pass along electron transport chain
Through series of redox reactions
Energy is released from electrons
Protons/H+ move into intermembrane space using the energy released from the electrons Protons/H+ diffuse through channel protein and ATP synthase
To form ATP from ADP and Pi.
Electron, proton and oxygen react to form water
Control of blood glucose
Glucagon
Glucagon is made in alpha cells of islet of Langerhans Released into blood
Glucagon binds to specific receptor.
On target membrane - muscles and liver
Activates adenylate cyclase on inside of membrane
ATP converted to cyclic AMP
cAMP activates protein kinase
Protein kinase hydrolysis glycogen to form glucose (glycogenolysis)
Facilitated diffusion of glucose out of target cells using a channel protein embedded in the membrane Increases blood glucose levels
Digestion of protein
Endopeptidase produced by the stomach wall
Hydrolyses internal peptide bonds with protein
Proteins hydrolysed to form polypeptides
Endopeptidase causes the formation of polypeptides with many ends
Exopeptidases produced by the pancreas hydrolyse peptide bonds at the ends of the polypeptides
Polypeptides are hydrolysed to form dipeptides
Dipeptidases embedded in the membrane of the small intestine wall hydrolyse the final peptide bond to form amino acids
DNA replication - Theme
If nucleotides and/or ATP are not available, then DNA will not be copied efficiently by semi conservative replication during the S phase of the cell cycle. This would result in less mitosis taking place and leads to an inability to repair damage done to tissues. A wound in the skin that damages a blood vessel could not be repaired and pathogens are more likely to enter the body and cause an infection Stem cells would be unable to repair damage to the wall of blood vessels which would increase blood loss at a wound.
Light independent reaction - Theme
The NADPH and ATP are important as both are required to reduce the glycerate-3-phosphate to make triose phosphate. If this did not take place the plant would produce less carbohydrate and other organic molecules. The glucose can be converted into beta glucose and condensed to form cellulose which is needed to form the cell wall of any new plant cells produced during mitosis. This allows the plant to grow and produce biomass which feeds the animals in the habitat.
Protein synthesis - Theme
If nucleotides and/or ATP are not available, then the haemoglobin gene may not be transcribed to make mRNA and less haemoglobin protein would be made on the ribosomes. Without haemoglobin the delivery of oxygen to the body’s tissues will be severely reduced. The terminal electron acceptor will not be readily available for the final stage of oxidative phosphorylation in aerobic respiration. As a result less ATP will be produced and the electron transfer chain will be unable to take any more electrons from NADH. The Krebs cycle, link reaction will no longer continue as there will be no oxidised coenzymes present. Only anaerobic respiration will take place and very little ATP will be available for ….add a theme from oxidative phosphorylation
Oxidative phosphorylation - Theme mammal
All cells require ATP from respiration to provide the energy needed for metabolism. ATP is hydrolysed to form ADP and an inorganic phosphate ion. This reaction is catalysed by ATP hydrolase. The energy released is used in the proximal convoluted tubule of the kidney to reabsorb all the glucose that has been removed from the blood in ultrafiltration. This reabsorption involved cotransport of glucose with sodium ions. This glucose is needed to maintain the blood glucose concentration and provide a respiratory substrate for all cells.
Oxidative phosphorylation - Theme plant
All cells require ATP from respiration to provide the energy needed for metabolism. ATP is hydrolysed to form ADP and an inorganic phosphate ion. This reaction is catalysed by ATP hydrolase. The energy released can be used for the active uptake of nitrate ions in root hair cells. Thes nitrate ions can then be added to other organic molecules to form amino acids. These amino acids are available in plants to synthesis proteins at the ribosomes.
Oxidative phosphorylation - Theme muscles
The attachment of ATP to the myosin head in a muscle causes the actinomyosin bridge to break. Calcium ions initiate the hydrolysis of ATP by ATP hydrolase and the energy released is used to ‘re-cock’ the myosin head , ready for the next powerstroke. Organisms with stronger muscle contraction can run faster and avoid predators. They are more likely to survive and reproduce passing their beneficial alleles on to the next generation. The frequency of these beneficial alleles increase in the population and leads to direction selection.
Oxidative phosphorylation - Theme mitosis
All cells require ATP from respiration to provide the energy needed for metabolism. ATP is hydrolysed to form ADP and an inorganic phosphate ion. This reaction is catalysed by ATP hydrolase. During mitosis the spindle fibres contract using the energy from ATP. The chromatids are pulled to opposite poles of the cell during anaphase, eventually creating 2 genetically identical daughter cells. This cell division allows growth and the constant replacement of cells in the body eg replacing cells of the he epithelium of the ileum.
Oxidative phosphorylation - condensation
The ATP is important as it is used in condensation reactions required to produce polymers. In semi conservative replication, DNA helicase breaks the hydrogen bonds joining the double helix together. DNA nucleotides diffuse and hydrogen bond to the template strand using specific complementary base pairing: guanine with cytosine and thymine with adenine. DNA polymerase uses the ATP, released in oxidative phosphorylation, to catalyse the production of phosphodiester bonds and form the newly synthesised strand of DNA. With out ATP this process would not be possible and the cell would be unable to undergo cell division.
Control of glucose theme
Blood glucose concentration can not be controlled if ATP is not converted to cAMP by the enzyme adenyl cyclase. This would result in less protein kinase being activated and less glycogenolysis taking place. The water potential of the blood plasma will increase. Water will enter cells by osmosis through the aquaporins in the cell membrane. The cell cytoplasm will increase in volume and could eventually burst as the membrane cannot not withstand the pressure placed on it. The tissues will not function effectively.
Control of glucose - Theme
Blood glucose concentration can become too low if not controlled by the production of cAMP when glucagon enters the receptors on the liver cell membrane. Less glucose will be delivered to the cells via the blood plasma and tissue fluid. Therefore less glucose diffuses into cells through their membrane and this would reduce the rate of respiration leading to less energy being released. This would lead to less entry for …. chose from options in oxidative phosphorylation themes
