CULMINATION OF EVERYTHING PPQ'S Flashcards
vitamin A deficiency, cornea drying out
- passage of light through cornea blocked
- cornea needs to be transparent
- could lead to blindness and impaired vision
why animals such as frogs are used to study an ecosystem
good indicator species, population changes in the animal species (e.g frogs) indicates changes in the the environment.
population would change with:
the amount of food available
the amt of predators in the ecosystem
their numbers if an indication to how well the ecosysten is doing
why is energy lost or how is it lost in a food chain
energy and biomass lost at each successive trophic level in forrm of ORGANIC excretory products such as urea, used in respiration, growth and repair, released as heat, in the form of faeces
graphs rules and food chain and diagram rules
scale
axes labelled
title CAPITAL LETTERS UNDERLINED
no cross lines
PENCIL ONLY
RULERS
STATE TROPHIC LEVELS
SIZE OF FOOD WEB DECREASING AS IT MOVES UP
STATE WHAT THE ANIMALS ARE PRODUCER, CONSUMER TERTIARY QUATERNARY
arrows
punnett square labels
- Let CAPITAL LETTER represent Dominant trait
- Let common letter represent recessive trait
- parent phenotype: father with X mother with
- parent genotype e.g AA X aa
- Gametes separte genotypes e.g. A A X a a
- Fertilisation (darw punnett square)
- offspring (F1) genotype: draw all genotypes
- offspring (F1) phenotypes: include gender
- phenotype ratio: 1 : 1, 1:2, etc
- percentage
Why are antibiotics used to treat tuberculosis (any bacteria caused disease) no longer effective
Over time, some of these bacteria became naturally resistant to the antibiotics. These bacteria would survive when persons take
these antibiotics and be able to reproduce and produce offspring that are also resistant because they would inherit the genes. Eventually more surviving bacteria will be resistant to the antibiotics.
The sequence of events occuring after pollination occurs all the way to the formation of the seed/fruit
When the pollen grain lands on the stigma, a pollen tube grows down the style and enters the ovule inside the ovary via the micropyle. The pollen divides into two
male nuclei while in the tube. One nucleus fertilizes the ovum inside the ovule and a zygote is formed. The integuments of the ovule harden and become the testa or
seed coat and the ovary becomes the fruit whose walls are called the pericarp.
to recognise the dominant trait
usually the phenotype/genotype/allele/trait produced or shown in larger quantities
Role of cotyledons
The cotyledons are a food reserve **(protein starch and/or lipid) **and get smaller as enzymes activated by water breakdown the food to provide the nutrients for the leaves to grow bigger. They support the plant until the leaves are big enough to photosynthesize and nourish the plant.
Protein digestion in the stomach and small intestines duodenum ileum
Protein digestion by the enzyme pepsin is suitable in the stomach due to the optimum acidic pH as a result of hydrochloric acid produced there. It also takes place in the small intestine (duodenum) where trypsin from the pancreatic juice works at optimum pH.
How is body temperture regulated? (6 marks)
In the day time his blood vessels (capillaries AND ARTERIOLES ) enlarge (VASODILATION dilate) so that the blood comes closer to the skin so that it will be cooled as heat is lost to the outer atmosphere. His sweat glands excrete sweat which cools the skin as it evaporates. Also, the erector muscles on his hair roots relax so that no hot hair is trapped on his skin. However, at night when it is cooler, his blood vessels decrease (VASOCONSTRICTION constrict) in size to conserve heat and the erector muscles on the hair roots of the skin contract to raise hair up to trap air to keep a warm layer of air around the body to insulate it. This process is homeostasis
brackish water
estuaries, mangrove swamps, midpoint of freshwater and sea water
human activities on mangrove ecosytems any swampy aquatic ecosystem
by persons hunting for pearls; cutting down mangrove trees which would destroy the habitat; breeding site and food source for oysters that live,reproduce and may feed on their roots; agricultural and industrial activities near to mangrove swamps result in harmful chemicals washing into the mangrove swamps and may be toxic to oysters.
Osmoregulation
an example of homeostasis but involves regulation of the osmotic potential of body fluids to maintain a balance in water content between
the inside and outside of cells.
Describe how the insulin gene/desired
gene engineering
The insulin gene/desired
gene is isolated from human DNA/pancreas cells with the use of specific enzymes and then inserted into a vector/plasmid taken from the E. coli.
The altered vector/plasmid is then introduced into the E. coli and the desired gene is inserted into the organisms’ DNA/genome. The genetically altered E. coli will then express the insulin gene/produce significant amounts of insulin when it reproduces. The insulin is then extracted
and purified for use by humans.
Candidates were told that a biologist discovered flowers of a species of plant with no male
reproductive parts. They were expected to use this information and suggest a method
by which this plant reproduces and state three advantages of the method.
could reproduce either asexually (for
example, by means of stem cuttings or root tubers) or by way of cross-pollination, using pollen from flowers of another related plant species.
**reading graphs **
READ INSTRUCTIONS STATE OR EXPLAIN ONE MARK OR TWO
READDD
0 C to 10° C
there is little or no energy to cause the collision of the substrate with the enzyme active site for a
reaction to take place.
Between 11° C to 40° C, the increasing temperature increases the kinetic
energy of enzyme and substrate molecules and this causes an increase in enzyme activity due to an increase in the number of substrate molecules that collide with the enzyme. As more substrate reacts with the enzyme active site, more product (oxygen Mn this case) is therefore
produced.
While most candidates were able to state that the enzyme works best at 40 C and
that they are denatured at temperatures above 40° C, only a few of them were able to fully
explain that because enzymes are proteins, they lose their three-dimensional structure at high
temperatures and the resulting change in the structure of the active site prevents it from reacting
with or binding to the substrate.
How is oxygen lost from blood?
haemoglobin in red blood cells carries oxygen in the form of oxyhaemoglobin and that oxygenated blood is transported from the lungs and pumped by the heart to the rest of the body. oxygen is released from the haemoglobin in the region of the
cells/tissues where oxygen concentration is low; so oxygen will diffuse into the cells where it is used for aerobic respiration.
Difference between plant cells and animal cells in water or a solution more dilute than its cytoplasm
animal and plant cell both expand in dilute solutions but the presence of the cell wall (made of cellulose) prevented the plant cell from bursting, while animal
cells burst as the surrounding cell membrane is unable to withstand the pressure exerted by the expanding cytoplasm of an animal cell caused by water particles moving into it (osmosis)
protoplasm
nucleus and cytoplasm
plasmolysed (flaccid)
candidates were asked to describe an approach, other than selecting seeds that the farmer could have adopted for introducing new traits in his tomato crop:
THIS IS ARTIFICIAL SELECTION
a breeding programme (artificial selection) whereby the desirable gene is identified (from plants in the wild) or seeds from the crosses are planted and
the offspring screened for the desired trait. These are then crossed and the offspring with the desirable gene are selected and propagated.
Or the crosses are made between the crop plant and a relative which has desirable traits (for example, disease resistance, better quality fruit).
one way in which the pattern of growth in plants differs in From that in animals.
Plants grow due to cell division in
defined areas, such as the meristems in their shoots and roots or cambial tissue in stems, while animals grow due to cell division in almost all parts of their bodies.
Plant growth is seasonal and occurs throughout most of their lifetime in response to external environmental conditions such as light, while animals have stages in their lifetime where growth occurs in response to the availability of food
