General AS Exam Q Flashcards
Population small and scattered in isolated areas. Why this speeds up extinction?
- inbreeding leads to small gene pool
- less likely to adapt to environment
- all wiped out by same disease
How zoos can aid conservation?
- captive breeding programmes
- promote conservation projects
- education and awareness
Adv +disadv of lack of nuclei + other membrane bound organelles in erythrocytes?
-more space to carry O2
- limited life span
- no respiration by mitochondria
Why erythrocytes don’t make use of any of the oxygen they transport?
- lack mitochondria so no aerobic respiration
- moved by mass slow so don’t need energy to move
How mass flow of phloem sap occurs?
- assimilates enter sieve tube element at source
- decreases psi
- water enters down psi
- increases hydrostatic pressure
- assimilates leave phloem at sink + psi increases
- water leaves down psi + decreases hydrostatic pressure
Why can expiration be a passive process?
-it doesn’t use muscle contraction; the muscles just relax
Effects of smooth muscle contraction in airways on ventilation?
- rendition in diameter of bronchi + bronchioles
- less air can be inhaled
- gasping
- increases breathing rate
What breathing instructions given to someone who’s vital capacity is being measured?
- breathe out as hard as possible
- breathe in as much as possible
Role of checkpoint after synthesis?
Checking that DNA has been replicated properly
Why students t test not suitable?
-cannot calculate mean or SD from data
Size of ribosomes in fungi?
80s
Which kingdom lacks membrane bound organelles?
Prokaryotae only
Which taxonomic group will contain least no. Of species?
Genus
Which taxonomic group will have the highest number of species?
Phylum
In what stage of meiosis do chromosomes condense?
-prophase 1 and 2
From which part of the body has the blood come if it is entering from inferior vena cava?
Abdomen
Which blood vessels are sphincter muscles found?
Arterioles
What makes lub sound
Closing of bicuspid valve
What makes dub sound?
Closing Of semi lunar valves
Why add ethanol in test for lipids?
Dissolved the lipid
Why facilitated diffusion requires no metabolic energy?
- movement down conc gradient
- particles have their own kinetic energy
Why - cannot pass through membrane?
- phospholipid acts as a barrier
- molecules too large
What is an autoimmune disease?
Abnormal immune response against tissues morally in the body
Sources of natural substances that can help develop new medicines?
Plants
Microorganisms
Sources of error In potometer investigation?
- error in reading position of meniscus
- leaks in apparatus
- shoot not cut underwater
Ethical issues with embryonic stem cells?
- embryo is killed
- embryo cannot give consent
- use of excess embryos from IVF
- debate about when life begins
How to observe position of xylem vessels
Put in stain
Then cut across
How xylem vessels of hydrophytes differs from dicotyledonous?
- less lignin
- thinner walls
How xylem vessels of xerophytes differs from dicotyledonous?
- more lignified walls
- thicker wall
Similarities of xylem and phloem?
- both made up of cells joined end to end
- both complex tissue
Differences between xylem and phloem?
- xylem is lignified phloem isn’t
- xylem has pits phloem doesn’t
- xylem has no cytoplasm or organelles. Phloem does
How trachea of a mammal is different from trachea of insect?
- Mammals have just 1. Insects have multiple
- mammals have c shaped rings. Insects have spiral support
- mammals have ciliated epithelium. Insects do not
Why population of habitat decreases?
- more predators
- more diseases
- more interspecific competition
- lack of management leasing to loss of habitat
Why population decreases less?
- conserve hedgerows
- fewer predators
- more open space for breeding sites
Benefits of genetic biodiversity?
- allows for adaptation to changing environment
- provides variation for natural selection
What would you use to test conc of glucose without using colorimeter?
Biosensor
How molecular structure of glucose + cholesterol is similar?
- both have C and H atoms
- have OH groups
Property of glucose that allows it to be transported in blood?
Soluble
How the root hairs of plants which live in areas with little water potential are adapted?
There is a lower water potential inside root hair
Advantages of binomial naming system?
- recognised worldwide
- know which genus + species it belongs to
- avoids confusion as there are diff common names for the same organism
What is wrong with writing Plasmodium Vivax?
- not italicised
- not underlined
- capital letter on specific name
How mosquito transmits malarial parasite to human?
- mosquito is vector
- parasite present in mosquito saliva
- feeds on human + parasite passes from saliva to blood
Problems with using insecticides to fight spread of malaria?
- insecticide resistance
- destruction of species is ethically wrong
- might cause unintended health problems in humans
Which lymphocytes are matured in thymus?
T lymphocytes
Which lymphocyte secretes substances which kill infected cells?
T lymphocytes
Which lymphocytes manufacture antibodies?
B
Which lymphocytes undergo clonal expansion?
Both
Which lymphocytes activate other lymphocytes?
T
How to draw graph for how antibody conc would change for 2nd time infection?
- higher peak
- steeper initial increase
- appear more quickly than 1st time
What is hinge on antibody for?
Flexibility
What is variable region on antibody for?
Binding to antigens
What is constant region on antibody for?
Binding to phagocytes
Why influenza vaccine has to be changed each year?
- virus mutates each year + have different antigens
- antibody produced needs to match new strain
Difference between primary and secondary immune responses?
-secondary starts earlier, faster + produces more antibodies
Role of memory cells when influenza enters body?
- recognise virus
- forms plasma cells
- make antibodies
- responsible for secondary response
Why dr would not prescribe antibiotics for influenza?
It effective against virus
X is an enzyme present on influenza. Enzyme breaks down host cell membrane + allows virus to leave.
Y is an inhibitor. How could y inhibit x?
- y is a competitive inhibitor
- complementary shape to active site + thus competes for active site
- prevent substrate binding to active site
- y is non competitive inhibitor
- fits into allosteric site +changes shape of active site
- prevents formation of ESC
Which ion is required for the hydrolysis of starch by an enzyme?
Cl-
How to reduce uncertainty of data
Use more precise apparatus
What happens when you soak something in ethanol?
Dissolves phospholipid bilayer
How to calibrate colorimeter?
Set to zero absorbance using distilled water
Why important to calibrate a colorimeter?
So values are all measured to same standard
What happens during metaphase?
- chromosomes align at equator of cell
- spindle fibres attaching to centromeres
Covalent bond which links 2 cysteine amino acids?
Disulfide
Why mosses do not need structures like xylem or roots to survive?
-large SA:V ratio
Why those of immunity does a vaccination give you?
Artificial active
Which type of phloem cell aphid inserted for get sap?
Sieve tube element
How to test for presence of sucrose?
Non reducing sugar so boil with acid
Add Benedicts reagent
Why starch not transported in phloem sap?
- not soluble
- makes sap thick
Why sucrose suitable for translocation?
- not likely to be used by mitochondria for energy
- not likely to diffuse out of sieve tubes
Term for isolated population developing slightly different characteristics to mainland population?
Intraspecific variation
Why x and y cannot be classed as diff species?
- can produce fertile offspring
- not enough phenotypic differences
Evaluate with reference to genetic biodiversity problem of small population?
- genetic diversity decreases as small gene pool and proportion of polymorphic loci is small
- homozygosity increases as inbreeding will occur as closely related animals will breed
- many be genetic erosion which is a loss of alleles
- if highly susceptible to disease it gives them low potential for adaptation to future change
- new alleles may arise as mutation but as slow as few generations per year
Precautions that need to be taken when setting up potometer to ensure no air present?
Setting up:
- cut stem underwater so no air can enter xylem +can obtain continuous column of water
- have apparatus underwater so no air can enter apparatus
- joints sealed tight
Precautions that need to be taken when using potometer to ensure no air present?
- do not allow air bubble to move too far so doesn’t enter xylem
- use syringe to move air bubble so same air bubble can be re used
- keep shoot supported to avoid breaking water column
Why you could get anomalous results when using potometer?
- bubble kit dully returned to starting position
- misread ruler
- temp/ light increased
Why have control?
Compare effects of their conditions
Why better to use capillary tube than calibrated pipette to measure water uptake?
Has more calibration marks
When measuring water uptake of 2 diff shoots, how to ensure valid?
- controls leaf area
- calculate transpiration rate per unit area
How H+ ions move out companion cell?
Active transport
How to ensure confidence in results?
- repeat experiment
- calculate mean
- identify anomalies
Why SA:V ratio of organism determines whether it needs circulatory system?
-large organisms have small SA:V so rate of diffusion too slow for sufficient uptake of nutrients
Functions of triglycerides in organisms?
- energy storage
- energy source for respiration
- thermal insulation
- buoyancy
Pattern of melting point for lipids?
-the fewer H the lower the melting point because it gives a more kinked chain + molecules less uniformly packed together
Similarities + differences between DNA nucleotide + ATP?
- both have penthouse monosaccharide
- both have phosphate group
-ATP has 2 additional phosphates
Deoxyribose replaced w ribose
Rules on drawing diagrams?
- use sharp pencil
- include scale bar
- make sure diagram takes up at least half of space
- title
- no shading
- continuous lines
Why key is described as dichotomous?
Each q has 2 options
