PRES Flashcards
Name the four chemical components that are present in all proteins.
C, H, O, N
Name the smallest unit of protein.
Amino Acid
Name the bond formed when the smallest units of protein join together.
Peptide bond.
Give one structural role of protein in living organisms.
Keratin in hair.
Name a test, or give the chemicals used, to demonstrate the presence of protein in a food sample.
Sodium Hydroxide and copper sulfate.
Describe the colour change that indicates a positive result in the test for protein.
blue to lilac.
Outline the importance of recycling elements such as carbon and nitrogen in nature.
To return nutrients to the environment so they can be reused again.
Give one specific reason why organisms need nitrogen.
Essential for production of amino acids.
State one role of micro-organisms in the carbon cycle.
Decomposition
Name the family of plants that has a symbiotic relationship with nitrogen-fixing bacteria.
Legumes
Distinguish between the process of nitrogen fixation and nitrification that takes place in the nitrogen cycle.
Fixation: N2 converted to nitrates
Nitrification: Ammonia converted to nitrates and nitrites.
Give a biological similarity between the nitrogen and the carbon cycle.
Both involve microorganisms.
State the difference between Stage 1 and Stage 2 of aerobic respiration.
Glycolysis: does not require oxygen
Krebs: requires oxygen.
By what name is Stage 1 also known?
Glycolysis
Name the 3 - carbon compound formed at the end of Stage 1.
Pyruvate
What happens to the product you named beforehand before it enters the Krebs cycle in Stage 2?
Converted to Acetyl Co Enzyme A.
Briefly describe the fate of any one named product in the Krebs cycle.
NADH
Enters the electron transport system.
What is meant by genetic engineering?
Artificial alteration of genes.
Outline what happens in each of the following stages of genetic engineering.
Isolation: removal of the chromosome and plasmid from the host DNA.
Expression: production of the required protein by the bacteria with the recombinant DNA.
What is the function of plasmids in genetic engineering?
Acts as a vector.
Name the enzyme involved in the ligation stage.
DNA ligase.
State one application of genetic engineering for an animal and micro - organism.
Animal: Sheep produce a protein to treat emphysema
Microorganism: production of insulin.
Endothelium is more…
Elastic fibre is more…
Collagen is more…
Very inside
Mid inside
Outside
How does the endothelium and elastic fibre help to move the blood through the veins?
Endothelium: smooth surface allows for better blood flow
EF: allows veins to stretch.
Name the type of tissue that lines blood vessels.
Endothelial
Other than blood cells, carbon dioxide and oxygen, name a substance that is transported in the blood.
Hormones.
State the function of the lymphatic system.
It contains white blood cells which fight off infections.
Give one way in which lymph differs from blood.
Travels slower than blood.
State the function of the eyepiece and stage.
- magnifies image of the object.
- supports the slide.
Describe how your prepared the cells from a named plant for examination.
Peel thin layer of onion skin using forceps.
Place on slide and add drop of iodine.
Place coverslip over sample at an angle to avoid air bubbles.
Examine under microscope, start with low power before switching to high power.
How did you alter the amount of light shining on the cell sample?
Adjusted by using diaphragm
Explain how you calculated the magnifying power of the microscope.
Eyepiece lens magnitude x objective lens magnitude.
What is meant by the optimum activity of an enzyme?
Conditions at which the enzyme is the most active.
Other than temperature, state one condition that will denature an enzyme.
PH
Name the enzyme you used in the investigation of the effect of heat denaturation on enzyme activity and describe experiment.
Catalase:
1. Blend celery and filter the liquid to get the extract.
2. Set up two test tubes.
3. Add hydrogen peroxide and washing up liquid to both.
4. Heat one test tube to 80 degrees using a water bath.
5. Other test tube should remain at room temperature.
6. Measure the height of the foam produced in both test tubes.
Compare the results that you obtained in the experiment with the control.
Control has a high foam production while the heated tube has little or no foam as the heat denatured the enzyme.
Which three chemical elements are present in all lipids?
C, H, O
How do fats and oils differ at room temperature?
Fats are solid and oils are liquid.
Give one way phospholipids differ from triglycerides.
P - 1 glycerol, 2 fatty acids, and a phosphate group.
T - 1 glycerol, 3 fatty acids.
Give one metabolic role of lipids in cells.
Energy source for respiration.
Give on structural role of lipids in cells.
Phospholipid bilayer in membrane.
Name one fat soluble vitamin.
D
What is a hypothesis?
A possible explanation for an observation.
State two principles of good experimentation.
Replication
Large sample size
Outline the steps of the scientific method that follow the design of an experiment.
- Come up with a hypothesis
- Conduct an experiment
- Do data analysis
- Form a conclusion
State one limitation of the scientific method.
Human error.
To which type of plant tissue do xylem and phloem belong to?
Vascular.
Give one function of xylem.
Transports water and dissolved minerals from the roots to the rest of the plant.
Give on function of phloem.
Transports food and hormones to all plant cells from the leaves.
One way to identify a monocot stem.
Vascular bundles are scattered.
State the location of the tissue containing xylem and phloem in a transverse section of a root.
Central region
Are cell walls only found in plant cells?
No
Is a turgid cell have a lot of water?
No
Do fermentation not use oxygen?
Yes
Is DNA only found in the nucleus?
No
Is there no hydrogen bonds in a molecule of DNA?
No
Are adenine and guanine purine bases?
Yes
Are chromosomes composed of DNA and protein?
Yes
Explain the term genetic engineering?
Artificial alteration a gene
Cutting looks like..
Insertion looks like..
Expression looks like..
C. section of circle missing
I. circle with white bit in the host cell
E. Goes to product
Give one application of genetic engineering for plants, m.o and animals
- Weed killer resistant crops
- Sheep produce a protein to treat emphysema
- Production of insulin
Distinguish between coding DNA and non-coding DNA.
CD: involved in direct production of protein.
NCD: does not code for protein.
Describe how you isolated DNA from the plant tissue.
- Add finely chooped onion to beaker.
- Pour in washing up liquid and stir.
- Put the beaker in a water vath at 60 degrees for 15 minutes.
- Cool the mixture by putting it in an ice bath for 5 minutes
- Blend the mixture for 3 seconds.
- Filter the blended mixture through coffee filter paper
- Add 3 drops of protease enzyme to 10ml of onion extract.
- Pour 10ml of ice cold ethanol onto the surface of the extract,
- DNA forms at the interface of the ethanol extract.
Explain the term enzyme
A biological catalyst.
State one advantage of immobilising enzymes.
Reusable
Name one enzyme you immobilised.
Amylase
Describe the procedure you used to imoblilise the enzyme.
- Yeast cells are immobilised using sodium alginate.
- Yeast suspension is mixed with sodium alginate and dropped into CaCl to solidify,
- The beads are left to harden for 20 minutes.
- Beads of alginate are washed three times and placed in a dropping funnel.
Describe how you examined the application of the immobilised enzyme.
- Sucrose solution was poured into the dropping funnel containing the beads.
- The product was released by opening the tap, and tested for a reducing sugar using glucose strips.
What is genetics?
The study of inheritance.
State the Law of Segregation in genetics.
A characteristic is controlled by 2 genes which separate at gamete formation.
Most mutations are not passed on from one generation to the next, explain.
Because they occur in somatic cells.
Write down a balanced chemical equation to summarise aerobic respiration.
C6H12O6 + 6O2 -> 6CO2 + 6H2O + ATP
What type of metabolic reaction is aerobic respiration?
Catabolic
Give two differences between aerobic and anaerobic respiration.
- A needs oxygen while AN doesn’t.
- A produces more ATP while AN produces less of it.
Name the first stage of aerobic respiration.
Glycolysis.
State the precise location in the cell where glycolysis occurs
Cytoplasm.
Explain how acetyl co enzyme A is produced
- Pyruvate enters mitochondrion
- One carbon atom is removed from pyruvate.
- The remaining two carbon molecules are oxidised
- NAD+ is reduced to NADH
- The acetate binds to coenzyme A.
How many carbon atoms are contained in one acetyl CoA molecule?
2
What is produced from pyruvate when oxygen is not available in a human muscle cell and in a yeast cell?
- Lactic acid
- Ethanol
ATP is a product of Stage 1 and Stage 2 of respiration. What does ATP stand for?
Adenosine Triphosphate
State 2 ways in which leaves of plants are adapted for photosynthesis.
- Chloroplasts
- Large surface area
Why is the dark stage given the alternative name of the light-independent stage?
Does not directly require light to occur.
Name two products of the light stage which are required for dark stage.
- ATP
- NADPH
Give 2 ways in which a horticulturist could increase the rate of photosynthesis in a greenhouse.
- Increase light intensity by using artificial lighting.
- Controlling CO2 levels.
Name the type of nutrition exhibited by organisms that carry out photosynthesis.
Autotrophic
Explain each of these:
1. Niche
2. Species
3. Ecosystem
- The functional role played by an organism in an ecosystem.
- A group of organisms that can interbreed.
- Community of organisms and their environment.
Give an example of a behavioral adaptation of the vole and explain how it helps the animal’s survival.
Destroying bunchgrass roots.
Reduces numbers of available perches for shrikes which makes it harder for them to hunt voles.
Suggest how the population of shrikes might respond if the population of voles declined significantly
It would decrease as well as voles are their primary food source so the decline would lead to less food therefore starvation
Name one factor that influences the size of human population
War
Explain:
1. Predation
2. Conservation
- The catching, killing and eating of prey by its predator.
- The wise management of our natural resources.
What is the importance in nature of recycling elements such as nitrogen and carbon?
Nutrients can be reused by organisms.
Describe main events of the carbon cycle.
- Plants absorb CO2 and covert it to glucose
- Herbivores eat plants which transfers carbon to their bodies.
- Carnivores eat herbivores which passes carbon along the food chain.
- Plants and animals release CO2 back into the atmosphere.
- When organisms die, decomposers break down their body
- Carbon becomes fossilized.
Nitrogen fixation:
Nitrification:
Denitrification:
- Nitrogen converted to nitrates.
- Ammonia converted to nitrites and nitrates.
- Nitrates converted to nitrogen gas.
What tissue is responsible for transporting food?
Phloem
S___ T___
S____ P___
C______ C____
Sieve Tube
Sieve Plate
Companion Cell
In which vascular tissue does water move through a plant?
Xylem
Where is xylem found in the stem.
Centre
Give two adaptations of the xylem that facilitates this movement of water.
- Lignin in cell walls.
- Hollow tubes.
What two scientists first explained the Cohesion Tension Model?
Dixon and Joly.
Describe the principal feature of the Cohesion tension model.
1.Water molecules stick together due to hydrogen bonds between them.
2.This cohesion creates a continuous column of water in the xylem vessels.
3. As water evaporates from the stomata in the leaves (transpiration), it creates a tension that pulls more water upwards from the roots through the xylem.
Explain the term turgor.
When water enters cells by osmosis.
Filling the vacuole.
Prevents wilting.
Name a feature of a plant cell that helps it to remain turgid for a considerable amount of time.
Cell wall
What happens when a cell loses turgidity?
Wilting
Suggest what may happen to an animal cell if it is subjected to the same conditions that result in a plant cell becoming turgid. Explain.
It would burst because it lacks a cell wall which would be able to withstand the pressure.
Define diffusion.
A passive process where molecules move from an area of higher concentration to an area of lower concentration.
Name 2 substances that enter a human muscle cell by diffusion.
Oxygen and glucose.
What term is used to describe the shape of a DNA molecule?
double helix
Name one purine base and one pyrimidine base found in DNA
Guanine and thymine
In tomato plants the allele for purple stem (P) is dominant to the allele for green stem (p) and the allele for the red fruit (R) is dominant to the allele for yellow fruit (r).
1. A tomato plant, with purple stems and red fruit, homozygous for both traits, was crossed with another tomato plant, which has green stems and yellow fruit. Indicate by means of a genetic cross the possible phenotypes and genotypes of the progeny of this case.
PPRR x pprr
PR PR
pr PpRr PpRr
pr PpRr PpRr
PpRr
All progeny have purple stems and red fruit.
Allele:
Dominant:
Homozygous:
Hetrozygous:
- alternative form of the same game.
- Prevents recessive gene from being expressed
- Two identical alleles
- Two different alleles
Cutting:
Transformation:
- Chromosome and plasmids cut using the same restrictive enzyme.
- The uptake of DNA into a cell.
Names the rings of DNA contained within a bacterial cell that may be used as cloning vectors.
Plasmids.
Explain the term competition:
The struggle between organisms for the same resource.
Contest C:
Scramble C:
- Active physical confrontation between two organisms where only one can win the resource.
e.g. Red deer interlock antlers - Each organism tries to acquire as much of the resource as possible. e.g. chicks in nest depending for parent food.
One advantage of the pine martin having a varied diet.
Avoid food shortages.
One type of adaptation necessary for an organism to survive.
Behavioral e.g. migration
What factors affect an animals population?
Food availability and disease.
Pollution:
Any harmful addition to the environment.
Outline the role of microorganisms in pollution control.
Biodegradation - break down pollutants to less harmful substances.
One pollutant and explain.
Slurry
Causes algal bloom which uses up O2.
Depletes it for animals and plants.
Two other problems with waste disposal.
Landfill Overflow
Can contain microorganisms that could cause disease.
How can waste be minimised?
Reuse bags when shopping.
Is photosynthesis anabolic or catabolic?
Catabolic because water and carbon dioxide is combined to form glucose.
Name the chemical substance whose molecules are essential to the absorption of light energy for the first stage of photosynthesis.
Chlorophyll
Function of ATP in cells.
Serves as a direct source of energy.
What is the source of protons used to make NADPH in pathway 2?
H2O
Outline role of NADPH in dark stage of photosynthesis.
Produces electrons and protons.
Name the other product of pathway two.
ATP
One source of CO2 used by plants in the dark stage.
Atmosphere
Openings in leaves that allows for gaseous exchange.
Stomata
How is the stomata controlled?
Guard cells
Why is an aquatic plant used for the investigation of rate of photosynthesis when subjected to various light levels or CO2 concentration?
Provides an easy, controlled environment.
How is the rate of photosynthesis measured?
CO2 uptake.
Evolution:
Process by which a species of organisms change over time due to a variation in their genetic traits.
Who developed the theory of evolution?
Wallace and Darwin
Name the type of bonding that holds the two strands of the DNA molecule together.
Hydrogen bonding.
One chemical difference between a DNA molecule and RNA molecule.
DNA: deoxyribose
RNA: ribose
Explain the term DNA profiling
Technique used to identify an individual based on their unique DNA pattern.
Suitable biological sample from which human DNA can be extracted.
Saliva
Application of DNA profiling
Paternity test
Law of Assortment
When gametes are formed, each member of a pair of alleles may combine randomly with either of another pair.
How might a hypothesis be tested?
By conducting an experiment
Whats the point of giving placebos to one group during an experiment.
To avoid bias
What term is used to describe organisms whose cells contain membrane bound nucleus?
Eukaryotes
Why the cell organelle involved in aerobic respiration is found in different numbers in different cells?
Mitochondria numbers differ depending on energy demand.
Other than a nucleus what cell organelle contains genetic material.
Mitochondria
What is a tissue?
Group of similar cells working together to carry out a function.
What is tissue culture?
State one requirement for successful tissue culture.
Give one application.
- pieces of tissue from an animal or plant are grown in a controlled environment outside the organisms body.
- Sterile environment
- Skin graft
