Essay Plans Flashcards
The importance of nitrogen-containing substances in biological systems
Biological molecules
ATP- adenosine triphosphate
An immediate energy source, used in metabolic process, movement, muscle contraction etc. Can easily be resynthesised
Nucleic acids- DNA and RNA
Bases are joined according to base pairs
Important: carrier of genetic information, provides genetic continuity from generation to generation
Transport proteins- carrier proteins and channel proteins
Important for the movement of substances but the movement is restricted to maintain the intergrity of the cell
Use is important in oral rehydration therapy given to treat diahorrea. There are Na+ channels in the epthelial cells to allow for reabsorption of Na+ which allows for water to re-enter the cells
Immunology
Humoural immunity- antibodies are produced by plasma cells (which are clones of B cells)
Importance: attaches to antigen a pathegon, prevents them entering cells, acts as markers so they can be destroyed by phagocytosis
Physiology
Haemglobin- changes affinity to oxgen depending on the environment by changing its 4’ structure
Important to make sure the body gets sufficient oxgen to carry out aeorbic respiration which produces ATP for metabolic processes
Importance of diffusion in organisms?
Synapses: when neurotransmitters diffuse across synaptic cleft
Countercurrent flow- in fish where water and blood flow in opposite directions
Gas exchange- how air enters the body of humans or insects
Plant responses to environment- diffusion of IAA from tip
Photosynthesis- product of the LDR diffuse into stroma for the light independent reaction
Importance of specific shapes?
Homeostasis- hormones bind to specific receptors on liver cells to stimulate a negative feedback mechanism
Important so an internal environment within restricted limits can be maintained
Insulin receptor is called an IGF i/ii receptors
Enzymes- induced fit model. Important so reactions can be catalysed for. Mention competitive and non-competitive inhibitors
Immunity- antigen-antibody complexes. Antibodies are produced by plasma cells and are complimentary only to one specific antigen
Synaptic transmission- neurotransmitters bind to specific neurotransmitter receptors
Important to allow for the generation of new action potential which can continue to transfer information for one neurone to another
DNA- has two strands so it can carry out semi conservative replication
DNA bases can bind according to base pairing rules
Haemoglobin- has a specific 4’ structure which can shape depending on what environment it is in in order to load or unload oxygen
Importance of responses to changes in internal and external environment of an organism
Behavioural
Taxis and Kinesis- Taxis is a directional responses to a stimuli
Kinesis is the random movement of an organims in response to a stimuli (speed and frequency of direction changes)
Eg. woodlice exhibit positive orthokinesis because they move faster to get away from an area that is too hot or too cold
Courtship behaviour- in response to seeing an individual of the same species but opposite sex. Allows for identification, synchornising of mating behaviour and formation of a pair bond
Immunology
Humoural response- T helper cells bind to receptor on a B cell and stimulate B cell clonal selection
or
Cell mediated response- phagocytosis
Physiological
Control of heart rate- example: baroreceptors in the carotid sinus detect an increase in heart rate and impulses are sent to the medulla and more impules are sent to the SAN via the parasympathetic route.
Coordination- stimuli causes an action potential to be generated if threshold is reached. Allows for transmission of information
Haemglobin- change in the quaternary structure to allow for the loading or unloading of oxygen
Movement of substances within living organisms
Ecology:
IAA and its effect on growth: phototropsim or geotropism
Respiration: oxidative phosphorylation, coenzymes FAD and NAD release their H+ and e- and enzymes go through ETC and protons accumulate in the inter membrane space
Translocation: sucrose is actively transported from the source to the sink (the mass flow theory)
EXTRA INFO; SUCROSE IS A.T INTO PHLOEM THROUGH A MECHANISM WHERE THEY ENTER THE CELL WALLS OF THE VEINS OF THE LEAF ATTACH TO SUCROSE TRANSPORTER PROTEINS
Physiology
Cardiac Cycle: movement of blood around the body which blood goes either to blood or the rest of the body
Digestive system: movement of lipids from the illeum to the epithelial cells to the Golgi Apparatus to combine with chloresterol to form chylomicrons which leave the cell by exocytosis
Importance of proteins in control of processes and responses?
Photosynthesis–> rubisco enzyme is needed for the combination of RuBP and CO2 to form GP
DNA replication–> DNA helicase needed for seperating the two strands and DNA polymerase need to create new strand
Respiration–> FAD and NAD act as coenzymes so carboxylation and oxidation reactions occur during the Krebs Cycle
Peptide hormones—> undergo second messenger model. Examples include glucagon and insulin for control of blood glucose concertration
Movement across membranes—> requires channel or carrier proteins
Importance of Ions in Biology
Ca2+–> in muscle contraction—> binds to troponin protein which causes tropomyosin to change shape and move of actin binding site
In synaptic transmission–> causes synaptic vesicles to fuse with presynatic membrane
Na+—-> influx of Na+ from voltage gated channels causes generation of action potential. In refractory period, these channels shut
——> in co transport, facilatated diffusion of Na+ into small intestine allows for glucose or amino acids to travel in with it
(name of glucose/na+ channel is called SGCT 1)
H+——-> pumped from inner mitochondrial membrane to inner membrane space
diffuse across ATP synthase to produce ATP
Importance of hydrogen bonding in biology?
Cohesion-Tension Theory- water molecules stick together to form hydrogen bonds and they form an unbroken column of water
Transpiration pulls puts xylem under tension
Structure of Cellulose- forms long straight chains which are bonded together to form microfibrils by hydrogen bonds. Provides strength and ridigity to cell wall
Structure of Proteins- Incorporated in 2’ and 3’ of a protein. In 2’ it forms alpha helixes or beta pleated sheets. In 3’ structure all of these 2’ structures joined together using ionic, disulphibe bridges or hydrogen bonding
Structure of DNA- complimentary nitrogenous bases on opposite strands are joined together by hydgrogen bonds
Gene technology- in PCR, hydrogen bonds are broken and primers anneal to complimentary bases by forming hydrogen bonds. PCR is used in the amplification process of DNA
Control of processes in cells and the importance of these cells
Homestatic controls:
Control of blood glucose levels- blood glucose levels detected by insulin or glucagon which is secreted and they bind to receptors on liver cells to undergo the second messenger model to activate enzymes such as gluconeogenesis
Control of water uptake- blood water levels are detected by the osmoreceptors in the hypothalamus which secrete more or less ADH in order to make sure more less water is lost from the body.
Control of cell division- tumour supressor genes (slow down cell division) and proto- oncogenes (stimulate cell division when growth factors attaches to a receptor)
Nerve Impulses - Refractory period (when voltage gated Na+ channels shut so discrete impulses can be made and it limits the number of action potentials that can pass along an axon) and the all or nothing principle
Transport across membranes- if a substance is not lipid soluble and/or small enough, it would have to pass through a carrier or a channel protein. To maintain intergrity of a cell
Use of DNA in science and technology
‘Other’/Forensic testing
Genetic fingerprinting- determining the number and type of tandem repeats/VTRN’s in a persons DNA
Used in paternity tests or in criminal forensics
PCR- used to amplify DNA and it is an example of ‘in vitro’ gene cloning
Useful for when you only have a small sample of DNA and is used in forensic examination
DNA Probes
Classification:
Species and Taxonomy- used to determine phylogenetic relationships
by looking at DNA base sequences
Genetic engineering:
‘In vivo’- using vectors to insert transgenic DNA into a bacteria or virus so it can replicate inside the body an organism
Relationships and interactions between organisms
Ecological- predatory/prey relationship succession interspecific predation Evolution- taxonomy- evolutionary relationships Behavioural- Courtship behaviour
Causes of disease in humans
pathogen- HIV lifestyle- epigenetics genetics- meiosis (non disjunction), cancer caused by mutations of proto oncogenes and tumour suppressor gene gene mutations
The membranes of different types of cells are involved in many different functions
Membrane function- phospholipid bilayer, prevents lipid insoluble substances entering the cell Immunology- B cells and T cells Phagocytes Processes- synaptic transmission Pacinian Corpuscle
The causes and importance of variation and diversity in organisms
Causes: Genetics- meiosis (crossing over, separation of homologous chromosomes, creates different combinations of alleles) Mutations Gene expression- transcription factors Epigenetics Ecology- succession Importance: genetic fingerprinting
The importance of receptors in living organisms
Behavioural- Taxis and Kinesis (earthworms moves readily and change direction to prevent drying out) Physiology- control of heart rate (detected by chemoreceptors and baroreceptors in the carotid sinus arteries) synaptic transmission (acetylcholine binds to AChR receptors on the post synaptic membrane) Immunology- B cells receptors (made of antibodies) present antigens and T helper cells (aka CD4 cells) stimulate B cell clonal selection Homeostatic- control of blood glucose, eg insulin binds to IGF1 or IGF 2 receptors on the liver cell to trigger the second messenger model
