Bio HL Flashcards
(24 cards)
Describe how the small intestine is adapted to carry out its function (7)
Peristalsis: Contraction of the muscle layer of the digestive tract, circular muscle contracts, prevents food from moving backwards. Longitudal muscle moves food along and mixes it. Allows for mixing chyme with enzymes.
SI produces maltase(enzyme):maltose-> glucose
Microvilli: increase SA for absorption, have a capillary network and lacteals for quick absorption. Embedded enzymes that stay in the membrane of the mucous.
Mucous ensures that lining isn’t damaged
Differences and similarities between non- competitive inhibitors. (4)
BOTH interfere with the functioning of the enzyme, reducing enzyme-substrate complexes.
Non-competitive inhibition:
Binds to an allosteric site, changing the active site, preventing enzyme from binding to substrate completely. Even if substrate concentration is increased, the rate of reaction will never reach max.
Competitive Inhibition:
Inhibitor binds to active site- structurally similar to substrate. The enzyme stays on and blocks the substrate from binding. But, if substrate concentration is increased, eventually the same substrate complex conc is reached.
Describe how humans synthesize antibodies.(7)
Steps in protein denaturation (4)
Temperatures that exceed the optimal temp of a protein break their bonds and alter their shape. High heat makes molecules move/vibrate, causing bonds to break. This process is not reversible, changing the re-alignment. This may also happen with pH as it alters the charge of proteins.
Explain why light dependent reactions are necessary for light independent reactions (7)
Light dependent reactions produce NADPH and ATP, used in the light dependent reactions. They are used to convert G3P into triose-phosphate. These molecules leave the Calvin cycle to form carbohydrates. To keep the process going, ATP(from light dependent rxns) is used to regenerate RuBP.
ATP is mainly created during chemiosmosis, NADPH is created by PSl
Similarities and differences between Xylem and Phloem (4)
Similarities:
Both are tubes that transport fluid.
Differences:
Xylem, are much wider, they transport water and minerals, uses tension to transport water due to transpiration so pull, ligned with lignin.
Xylem cells are alive.
Phloem, have a narrow lumen, transport sucrose from source to sink, cells are dead, have sieve plates.
Describe how water properties make it suitable to its function.(4)
Water is polar(+-).
Can form hydrogen bonds with other molecules, making it adhesive and cohesive, moving it up plants during transpiration(pull). Low viscosity (allows it to permeate small paths). High heat vaporization, ideal for plants retaining water during high temperatures.
Explain the process of transcription (7)
Write down how peat is formed.(4)
Formed from dead plants(eg moss). Forms in waterlogged areas such as swamps. Forms in anaerobic and acidic areas which inhibit bacteria (doesn’t allow proper decomposition)
How is water absorbed in the roots (4)
Roots actively pump ions and minerals into their system. This creates a higher solute concentration within the roots, passively allowing water to diffuse into root hair cells via osmosis.
Be able to draw an annotated diagram of a seed
How is nitrogenous waste removed from insects?(8)
Nitrogenous waste(ammonia) builds up in the hemolymph (between mid- and hind gut)This is absorbed my malphigian tubules and converted into uric acid(less toxic). The tubules also absorb sodium and potassium, resulting in high solute concentration, allowing water to follow via osmosis. This influx of water washed uric acid and ions into hindgut. In hind gut, hemolymph reabsorbs water and ions, making nitrogenous waste pastey. This is excreted via the anus.
Similarities and differences between transcription and translation(4)
Both aim to produce proteins.
Transcription occurs in the nucleus, translation in the cytoplasm. Transcription required RNA polymerase, translation required tRNA and ribosomes
Be able to draw an amino acid and show condensation rxn(3)
How are inorganic nutrients and energy moved through ecosystems?
Autotrophs absorb inorganic molecules and sun energy via photosynthesis and turn it into chemical energy. Inorganic CO2 , light a water is converted into organic carbohydrates. During cellular respiration, these compounds are consumed for energy in order to grow and develop. This energy can be transferred through trophies levels. Each trophic level, around 90% of this energy is lost through waste and indigestible materials (hair, bones). When organisms die, decomposes can recycle these organic nutrients , reusing them for individual development. Heat is lost.
Explain growth of the apex
How is the heart rate controlled?
Evidence that supports how parents could have children with any of the ABO blood groups
Why are blood concentration different in renal artery and vein?
Kidney contains cells that undergo cellular respiration. Renal vein contains filtered blood(to the body). This means, respiration reactants such as glucose and oxygen are much higher in the renal artery, because the cells of the kidney use up these reactants after the renal artery because they do respiration. Differently, CO2 is much higher in the renal vein because the kidney performed respiration. Urea concentration is much lower in the vein because it is secreted in urine through kidney (this agrees with general other toxins as they are also secreted via urine in collecting duct).
How does polypeptide chain synthesis occur in eukaryotic cells?
- this is talking about transcription and translation*
So that translation can occur via ribosomes, transcription in the nucleus converts DNA to mRNA. This mRNA is bound to a ribosomal complex and is read in sets of 3 bases (EPA sites). TRNA molecules collect single amino acids and deliver them to the E site, building a polypeptide chain. TRNA contains three bases “anticodons” which perform complementary base pairing. The mRNA moves through the ribosome via the movement of the tRNA (A-P-Exit). THi continues until a stoop codon is reached (causing polypeptide chain to detach from the ribosome).
Features of eukaryotic Chromosomes
They are linear structures supported by histone proteins. They appear in homologous pairs in diploid cells. Homologous chromosomes contain same sequence of genes- base sequence may differ due to different alleles. Most sequences code for proteins to be expressed, there are also non-coding areas
Give key steps of the Calvin experiment.
Algae were grown in a circular lollipop apparatus. A supply of light and CO2 was provided. Radioactive carbon is injected to track the carouse of photosynthesis. The algae was killed every 5 seconds by putting it into boiling methanol. This froze the reaction in time allowing the steps to be understood. These results were separated via 2D chromatography and then exposed on X-ray film as radioactive C stains paper.
After 5 secs: Radiactive G3P was identified (first stable molecule from carbon fixation (CO2+RuBP).
After 10 secs: Radioactive triose phosphate appeared, indicated G3P was converted into it.
After 15 seconds: Radioactive glucose and Ribulose Phosphate and RuBP showed up, showing RuBP is part of a cycle and being reformed.
Key points about causes and symptoms of sickle cell anemia.
Caused by a base substitution in the Beta chain haemoglobin gene where GAG is replaced by GTG. During transcription, valine replaces glutamic acid. This causes the Beta chain to not align or rectory, the protein doesn’t form right. When there is too little oxygen, haemoglobin crystallises, causing the RBC’s to crystalize, causing RBC’s to have crescent shapes. These shapes obstruct capillaries
Symptoms:
- Fatigue
-Pain
-Organ Damage
- Cells die
In heterozygous Hb^5 cases, person shows mild symptoms when Oxygen is low (high altitudes)
IN homozygous Hb^5 cases, death is possible
This gene mutation is prominent in malaria-prone countries as cells adapt to protecting themselves against the virus (RBC’s cant carry it).
