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