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
Why plants store food/benefits for plants when they store food
- withstanding prolonged
periods of harsh weather conditions such as drought/winter - to supply nutrients when light intensity is
low and the plants are unable to photosynthesize - for growth and development of the embryo during germination; for asexual reproduction
How does climate change increase mosquito/vector population?
prolonged high temperatures and rainfall may increase mosquito breeding and hence increase transmission of mosquito-borne diseases, such as dengue fever and malaria.
PEPPERED MOTHS
post- industrialization, the speckled (light coloured) form was poorly camouflaged and more likely to be eaten by
birds since the soot from factories during industrialization caused the tree trunks to be blackened so that the
dark form was now well camouflaged. The dark form now had the selective advantage (which belonged to
the pale speckled form when the tree trunks were lichen covered). Preindustrialization, both variants – the
speckled form and the black form
existed but the speckled form was well camouflaged on the lichen
covered trees, so less selection pressure was exerted by bird predation and they therefore existed in higher
numbers. A common misconception was that the soot caused the speckled form to mutate/adapt and become
dark in spite of the question stating that both variants existed. This example merely demonstrates one of the
ways in which natural selection operates, that is, due to camouflage.
ways plants use the glucose produced.
- the glucose is converted to sucrose/transported as
sucrose from the leaves to parts of the plant that require glucosel energy for example, growing points. - it is used in respiration to provide energy or for making cellulose/cell walls
- stored in the form of sucrose in fruits or starch in seeds, leaves, stems or roots.
- converted to make important nutrients crucial to the survival of the plant
fertilization.
After ejaculation in the vagina, sperm from the penis swim up the uterus to meet the ovum in the woman ‘s fallopian tube. The sperm that reaches first will penetrate the ovum and their nuclei fuse to form a zygote. This is called fertilization.
Meiosis VS Mitosis
- meiosis results in the production of cells containing half the number of chromosomes (haploid number
found in the parent cell while mitosis results in cells containing the diploid number or the same number of
chromosomes as in the parent cell. - Other differences such as crossing over/exchange of alleles takes place during meiosis but none occurs in mitosis;
- cells produced from meiosis are
genetically different from each other while those formed from mitosis are genetically identical
Accomodation
Accommodation is the process of changing the shape of the lens to focus on near or distant objects.
To focus on a near object – the ciliary muscles contract (i.e., shorten), suspensory ligaments slacken, the lens becomes thicker, this allows the light rays to refract (bend) more strongly.
To focus on a distant object – the ciliary muscles relax (i.e., lengthen), suspensory ligaments tighten, the lens is pulled thin, this allows the light rays to refract slightly.
How we see
Step 1: Light enters the eye through the cornea (cornea refracts the light rays)
Step 2: The pupil adjusts in response to the light.
Step 3: The lens focuses the light onto the retina
Step 4: The light is focused onto the retina.
Step 5: The optic nerve transmits visual information to the brain.
Step 6: The brain interprets the image allowing us to see it
Cell specialisation importance
- form tissue/organs which carry out specific functions in the human body.
- specialized cells/tissues|organs can carry out different life processes simultaneously;
body (processes) works more efficiently. - physiological diseases are caused by defective cellslorgans/systems so embryonic stem cells could be used to produce specialized cells to produce organs that can replace the defective one(s)
Stem cells
special human cells that are able to develop into many different cell types. This can range from muscle cells to brain cells. In some cases, they can also fix damaged tissues.
Cell specialisation
If a cell is specialized, it has unique structures that allow it to carry out its function in the body. All cells start as stem cells, which are cells that can become many other types of cells. They go through a process called differentiation to become specialized.
process by which a stem cells develops into another type ofc ell to carry out a particluar function, specilaisd cells can be grouped togther to form tissues and organs
COntrol of light entering the eye
The coloured part of the eye, the iris, is a muscular ring or sphincter which controls the amount of light entering the eye.
It causes the pupil to dilate (get bigger) in darkness so as to let in more light.
In bright light, the iris causes the pupil to constrict (get smaller), reduces the amount of light entering the eye, preventing damage to the retina.
Specialised cell found in nervous system
Motor neuron sensory relay
Phototrophism Gravitropism
Postive phototrophism- towards light
Postive gavitropism- downwards
Outcomes if two species compete for the same resources
Death due to starvation
Slow growth development and Reproduction
Migration
Population decrease in both
A food chain does not SHOW WHAT
OMNIVORES BECAUSE FOOD CHAINS ONLY SHOW ONE FOOD SOURCE
Asexual Reproduction
Budding- Hydra
Binary fission- bacteria
Vegetative propagation- potatoes sugar cane
Genetic diagrams
Alleles
Genotype
Phenotype
Diagram
Percentage chances
If it’s autosomal
NOT SEX LINKED
DO NOT INCLUDE SEX CHROMOSMES
X AND Y
Two functions of the human skeletal system
- Aids movement
- Produces blood cells (red bone marrow)
- Aids with shape and support
- Stores minerals (CALCIUM)
- Protects internal organs
Flexed arm of a human being
Biceps are in the front (right hand side)
Triceps are at the back (left back)
Joint in knee
Hinge
Joint in hip
Ball and socket
Similarity and difference between knee joint and hip joint
Similarity: free movement (synovial joints)
Difference: hinge joint provides motion in one direction while ball and socket provide motion in more than one direction
Ways in which an animal may be affected by a BROKEN LIMB
- Easily captured by predator
- Unable to reach or findbfood easily resulting in starvation
- Unable to reproduce
- Develop infection
- Slow movement
Difference between growth in plants and growth in animals
Mainly vertical vs both vertical and lateral
Faster and more noticeable
Slower and less noticeable within a short time
Uneven vs even..occurs all over
Continuous, continues growing throughout its lifetime
Stops at a certain point of maturity
Reasons for trends in diseases
Adaption
Variation
Structures of Bacterium that aid it in feeding and survival
Pili or fimbriae- protect bacterial cell from being eaten by phagocytes so it can continue to survive and develop
Flagellum- enables movement towards the target or host cell
Slime capsule- protects the bacterium from harmful chemicals and also helps it stick to target cell
Cell wall- provides protection form antibodies and phagocytes
Red blood cells vs skin cells
Skin cells vs nerve cells
Biconave smaller does not have a nucleus carries haemoglobin
Insulated with Myelin sheath and have axons and dendrities and synaptic knobs
Meiosis
Four unidentical daughter cells (EACH WITH HAVE THE NUMBE ROF CHROMOSOMES THAN THE FIRST CELL
Meiosis cocurs where
Ovaries
Testes testicles
Meisosis in flowering plants to produce gametes
Pollen (each pollen ahs two sperm cells)
Ovules
Why multicellular organism require transport systems vs unicellular organisms/plants
Reson #1
Multicellular organisms are bigger and have a lower surface area to volume ratio
-they need a tranport system to take substances to and from their many cells over relatively long distances and quickly before waste builds up
-tissues are generally larger and require large supply of substances
Reason #2 Exchange of substances directly between the external environment
- unlike unicellular organisms OR PLANTS most cells in Multicellular organisms are unable to exchange substances directly to the external environment by simple diffusion. Hence transport systems are needed to take these substances like waste such as co2 or oxygen to and from these cells EFFECTIVELY
Xylem adapted for its role
Dead- allows water to travel through continuously without absorbing water like a straw dead and rigid
Narrow- aids in capillary action move upwards against gravity without resistance
Tube like- easy passage of water aids in Capillarity
