Biology paper 3 Flashcards
Define niche
functional role of an organism in its habitat
What may occur when species share the same niche
they will compete with each other for the same resources
One of the species will be more successful and out-compete
the other species until only one species is left and the other is either forced to occupy a new, slightly different niche or to go extinct from the habitat or ecosystem altogether
examples where two species tried to occupy the same niche
speciesoccupy the same habitat (spruces and other conifer trees) but occupy slightly different niches as each species feeds at a different height within the trees
This avoids competition between the three species, allowing them to co-exist closely with each other in the same habitat
Species definition
Group of living organisms that are reproductively isolated and capable of producing fertile off spring. They are anatomically, behaviourally and physiologically similar.
3 types of adaptations
Anatomical - structural features such as horns, claws or feathers, that increase an organism’s chances of survival
Behavioural - behaviours such as courtship of defensive behaviours, that increase an organism’s chances of survival
Physiological, which refers to processes inside the body, such as venom production or the ability to digest cellulose, that increase an organism’s chances of survival
examples of behavioural, anatomical and physiological adaptations in sloths
Moving slowly, long alimentary canal/gripping claws/enzymes to break down lactic acid
how can mutations give rise to evolution
Variation caused by mutation, selection pressure, advantageous allele causes some individuals to survive and reproduce, allele passed to offspring, allele frequency increases in the population.
importance of amino acid sequence in protein structure
forms the primary structure of the protein/polypeptide. R groups allow bonds to form to hold tertiary structure in place.
how can organisms be held in taxonomic groups
idea that organisms with {
specific / particular / shared /
common / similar / eq} {
characteristics / features/ traits / eq } are placed in a group;
2. detail of how characteristics assessed, e.g. observable characteristics, behavioural similarities, similarities in DNA, molecular phylogeny;
limitation of using 5 kingdom
virus not included
Similar organisms are kept far from each other. For example- Unicellular and multicellular algae.
based on physical characteristics
Explain the change in classification that occurred in 1990 as a result of the work of Carl Woese
Based on the evidence that molecular phylogeny provided, it was determined that the organisms in the kingdom Prokaryotae would be reclassified into two separate domains - the Archaea and Bacteria
The evidence suggested that archaea and bacteria are less closely related to each other than scientists originally thought
Organisms from the other four kingdoms where placed in another domain - Eukaryota
Previously classification was based on physical features
what is molecular phylogeny
similarities or differences of molecules (such as DNA, RNA or proteins) between groups of organisms to determine how closely related they are
what is phylogeny
evolutionary history of different groups of organisms and can specify how closely related they are
Carl Woese proposed a 3 domain classification system. Name the 3 domains
The Archaea, Bacteria and Eukaryota
Describe how Woese work is critically evaluated
scientific findings published e.g. in a journal
2. idea of presented at scientific conference / eq;
3. idea of peer review;
4. (other scientists) repeat experiments (to confirm or validate findings / test reliability of data)
Woese suggested that organisms could be placed into taxonomic groups based on molecular Phylogeny. Explain what is meant by this statement.
idea that organisms with { specific / particular / shared / common / similar eq > < characteristics / features / traits / eg } are placed in a group ;
2. idea that taxonomic groups have specific differences ;
3. idea that phylogeny describes {evolutionary / genetic} relationship;
4. idea that molecular phylogeny based on similarities in { DNA / DNA sequence / proteins / eq ≥
List the sequence of taxa used in the Linnaeus classification system.
Kingdom, Phylum, Class, Order, Family, Genus, Species
Compare and contrast an algae cell with that of an animal cell
Chloroplasts, cell wall and vacuole only found in algae. Both eukaryotic with nucleus, plasma membrane, cytoplasm, mitochondria and ribosomes. Both can have flagella in some cases.
Which kingdom do the 4 phyla of algae belong to?
Protist
Suggest a ‘trace element’ that algae may provide for sloths
Fe, Zn, Cu Co, I
describe the structure of cellulose microfibril
cellulose is a polymer of beta glucose (1)
* (the glucose molecules are) held together by glycosidic bonds
(1)
* -glucose monomers form (long) straight chains (1)
* (the cellulose molecules are) held together by hydrogen bonds
(1)
* microfibrils are composed of many cellulose molecules
describe structure of cellulose cell wall
- cellulose (molecule) is a { polymer / chain / eq } of
B-glucose / eq; - cellulose molecules held together { by hydrogen bonds / as microfibrils }
- idea of arrangement of microfibrils in { parallel / net / mesh / criss cross / eq ≥ ;
- reference to { matrix / hemicelluloses /pectin / eq }
explain how structure and properties of starch are related to its function as a storage molecule
contains glucose needed for {respiration/energy} (1)
* insoluble so < has no osmotic effect / remains in the cell }
(1)
* amylose is coiled making starch compact (so more can be stored)
(1)
* amylopectin {is branched/contains 1-6 glycosidic bonds} so is rapidly hydrolysed
what disease causing protist causes malaria
Plasmodium
Describe structure of an antibody
Y shaped protein. Heavy and light strands, cross-bridges, variable region. Quaternary protein structure
What cells produce antibodies
Plasma cells . B cells
how vasoconstriction and vasodilation keep body temperature in a narrow range
During vasoconstriction the muscles in the arteriole walls contract, causing the arterioles near the skin to constrict and allowing less blood to flow through skin capillaries
Instead, the blood is diverted through shunt vessels, which are deeper in the skin and therefore do not lose heat to the environment
Arterioles have muscles in their walls that can relax or contract to allow more or less blood to flow through them
During vasodilation these muscles relax, causing the arterioles near the skin to dilate and allowing more blood to flow through skin capillaries
which part of brain responsible for vasoconstriction and vasodilation
Medulla oblongata
how shivering enable body temperature of 38 degrees
The hair erector pili muscles in the skin contract, causing hairs to stand on end
These muscles can be described as effectors, as they respond to a change in body temperature
This means they form form an insulating layer of trapped air,heat can therefore not leave by radiation
This is a reflex action in response to a decrease in core body temperature
Nervous control
The metabolic reactions required to power this shivering generate sufficient heat to warm the blood and raise the core body temperature
how brain reduces activity of sweat glands after exercise
thermoreceptors detect a decrease in temperature (1)
* {hypothalamus / thermoregulatory centre } sends fewer impulses to sweat glands
what is a tendon
Joins muscle to bone
define fatigue in terms of muscular contraction
Decreased ability to produce force i.e. weakness due to lower ATP production, build up of lactate due to anaerobic respiration
Compare and contrast fast and slow twitch muscle fibres
Slow Twitch fibres – for endurance; Red (contain much myoglobin); Many mitochondria; Little sarcoplasmic reticulum; Low glycogen content; Numerous capillaries; Fatigue resistant
Fast twitch fibres – for sprinting; White (little myoglobin); few mitochondria; Much sarcoplasmic reticulum; High glycogen content; Few capillaries; Fatigue quickly
reactant and product of anaerobic respiration and where does it occur
Glucose + 2ADP +2Pi 2ATP + 2 lactate
Cytoplasm
community
A group of different species found in an ecosystem or habitat.
Describe the role of ‘secretions on the sloth’s skin’ in preventing pathogenic infection in the sloth.
Anatomical, chemical barrier. Sebum makes skin oily, skin flora outcompetes pathogen micro-organisms so they don’t have enough resources and die.
Lactate (lactic acid) can build up in the muscles of a sprinter.
Suggest why the build-up of lactate may prevent any further increase in speed.
(lactate build up) causes {drop in pH / more acidic / increase H* /eq);
2. idea of this affects enzyme (activity / shape / eq] ;
3. this slows down {glycolysis / ATP production / anaerobic respiration / eg
4. reference to muscle contractions being affected;
Explain the fate of lactic acid after a period of anaerobic respiration.
reference to lactate in the blood / eg;
{transported to / broken down in / eq] liver;
lactate is {converted to pyruvate / eq) ;
this involves oxidation / production of reduced NAD /
eq);
pyruvate is then foxidised / eq);
reference to Krebs cycle;
{this requires extra oxygen / reference oxygen debt} /
eg
idea that carbon dioxide and water are produced;
Explain the importance of removing lactic acid.
Lactic Acid lowers pH. Enzymes denatured/ reduced activity. Less successful collisions/less enzyme substrate complexes. Directly impacts metabolic rate.
