What is the name of a germ killing substance produced by a bacterium or mould?
antibiotic or antimicrobial
Where is the greatest tropical diversity found in terrestrial ecosystem? aquatic ecosystem?
tropical rainforest and coral reef
Describe the difference between prokaryotic and eukaryotic cells.
|
| Prokaryotes | Eukaryotes |
| Meaning | “pro” = before “karyon” = nucleus | “eu” = good or true |
| Nuclear regions | - no nuclear membrane - DNA concentrated in an area called the nucleoid | - nucleus with nuclear membrane |
| DNA | - one large circular chromosome | - several linear chromosomes |
| Genome | - haploid | - diploid
|
| Complexity | - no mitochondria, chloroplasts, Golgi apparatus or ER - ribosomes are smaller - unicellular (may appear in colonies) | - normal complement of organelles - many be unicellular or multicellular |
| Size | - usually < 2mm | - usually > 2 mm |
| Cell division | - binary fission | - mitosis |
| Kingdoms | - bacteria and archaea - Escherichia coli (E. coli) | - protists, fungi, plants, animals - eg. Human cheek cell |
List the six kingdoms. Describe each one and give an example of an organism from each.
| Kingdom | Cell characteristics | Other characteristics | Examples |
| Eubacteria >10 000 described species | -Prokaryotic -Cell walls contain a unique compound -Cells are variable in shape and size | -Have diverse means of obtaining energy and nutrients – photosynthetic, chemotropic or heterotrophic -reproduce asexually | Escherichia coli Salmonella Nitrogen-fixing bacteria |
| Archaea >400 described species | -Prokaryotic -Cell walls and cell membranes have a unique structure -Most are extremely small | -Some colonize extreme environments -live in the digestive tracts of mammals and marine environments -reproduce asexually | Extreme thermophiles Methanogens halophiles |
| Protista >100 000 described species | -Eukaryotic -Cells have extreme diversity of cellular structure -Some have chloroplasts and cell walls | -may be heterotrophic or photosynthetic or both -have variable forms of movement -usually live in aquatic or other moist environments -reproduce asexually and sexually | Amoeba Kelps Green algae |
| Fungi >100 000 described species | -Eukaryotic -cell wall is composed of chitin -Most of multicellular -Cells have no chloroplasts | -All are heterotrophic -Most are terrestrial -reproduce asexually and sexually
| Mushrooms Yeasts moulds |
| Plants >250 000 described species | -Eukaryotic -All are multicellular -Cell walls are composed of cellulose -possess chloroplasts | -autotrophic and photosynthetic -Most are terrestrial -reproduce asexually and sexually | Mosses Ferns Conifers Flowering plants |
| Animals >1.2 million described species | -Eukaryotic -All are multicellular -Cells have no cell walls or chloroplasts | -all heterotrophic -Most reproduce sexually -Live in terrestrial and aquatic environments | Elephants Sponges Corals Insects Humans |
Describe the lytic cycle of a bacteriophage reproduction.
1. Attachment - bacteriophage attaches to outside of bacterial cell by tail fibres
2. Entry - viral DNA or RNA is injected into the host cell
3. Replication - host cell begins to produce viral DNA or RNA and proteins
4. Assembly - viral particles are assembled in the host cell
5. Lysis and Release - host cell bursts and viruses are released
What is the difference between homozygous and heterozygous?
homozygous - has two of the same alleles (eg. AA or aa)
heterozygous - has two different alleles (eg. Aa)
What is the difference between genotype and phenotype?
Genotype describes the genetic make-up of the organsim while the phenotype describes the physical appearance.
eg. genotype Bb phenotype: Brown hair
Describe two processes that produce variation during meiosis.
Crossing over
- non-sister chromatids in a homologous pair exchange genes.
- this allows for the recombination of genes on each chromosome and contributes to genetic variation
Random (independent) assortment
- The random alignment of homologous chromosomes along the equator during metaphase I
If a woman has blood type AB and a man has blood type O, what possible blood types will their children have?
IAIB x ii
|
|
IA |
IB |
|
i |
IAi |
IBi |
|
i |
IAi |
IBi |
The children will be type A or type B blood.
Compare the process of Mitosis to Meiosis.
| Mitosis | Meiosis | |
| Purpose | growth, repair, maintenance | production of sex cells with half the chromosome number and variation |
| Type of cell | somatic cells | gametes |
| Genome | diploid | haploid |
| Cells produced | two identical cells produced | four difference cells produced |
Describe 6 ways that plants are useful to humans.
production of medicine, food, building materials, fibres for clothes, aesthetic value, produce oxygen through photsynthesis
How does the structure of the leaf prevent water loss in a plant?
waxy cuticle
stomata can close
What is monoculture? What are some problems associated with monoculture?
Monoculture is the growing of one species over a very large area. Problems include crop specific pests, spread of disease and reduction of nutrients in the soil.
Describe how a hormone causes a response from a stimulus such as light.
- caused by differing amounts of auxin produced on the light and dark sides of the stem
- auxin accumulates on the shaded side of the stem causing the cells to elongate
- this causes the stem to bend toward the light
Describe some options that farmers have for eliminating crop pests.
Technology for Controlling Pests
a) Pesticides - many draw backs such as toxicity to other organisms, health problems in humans, biomagnification, resistance
b) Mechanical Control - trapping, catching, picking off or pulling out unwanted pests
c) Cultural Control - cultivation methods to discourage pests
ie. - plant plants that attract the pest insect’s predator between rows of crop plants
d) Sex Attractant Control - release sterile males so females will lay infertile eggs
- use pheromones to disrupt mating patterns
e) Biological Control - use pest’s natural enemies (predators, parasites, pathogens) - ie. ladybugs feed on aphids
Marigold’s scent repels some pests in vegetable gardens
f) Hydroponic culturing - growing plants with their roots immersed in water that contains dissolved nutrients
Where do you find the pyloric sphincter?
The pyloric sphincter is found between the stomach and small intestine.
How does the small intestine provide a large surface area for absorption?
very long (7m), villi and microvilli
What is the name of the vessels which supply blood to the heart muscle?
coronary arteries
What is the name of the flap of tissue that covers the trachea when you swallow?
epiglottis
Describe the following terms: tidal volume, vital capacity, residual volume, inspiratory reserve volume and expiratory reserve volume
Tidal Volume – the volume of air inhaled and exhaled in a normal breathing movement
Vital Capacity – the total volume of gas that can be moved in or out of the lungs
Residual Volume – the amount of gas that remains in the lungs and the passageways of the respiratory system even after a full exhalation
Inspiratory Reserve Volume – the additional volume of air that can be taken in, beyond a regular or tidal inhalation
Expiratory Reserve Volume – the additional volume that can be forced out to the lungs, beyond a regular or tidal exhalation
What is thetheoretical evolution history of a species or group called?
phylogeny
Changes in allele frequency due to chance that occurs most frequently in small populations is called....
genetic drift
Describe the difference between directional, stabilizing and disruptive selection.
Directional Selection
- favours an increase or decrease in the value of a trait from the current population average
- therefore favours individuals with a more extreme variation of a trait
- common in artificial breeding
Stabilizing Selection
- selection against individuals exhibiting traits that deviate from the population average
- therefore favours individuals with the average phenotype
- eg. Human birth weight (babies with low weights are often developmentally premature and less likely to survive. Those with heavier weight often experience birth-related complications that threaten the mother and baby.
Disruptive selection
- favour two or more variations of a trait that differ from the current population average
- therefore favours individuals with variations as opposite extremes
-Eg. Two types of flowers (small and large) are food sources for hummingbirds
What is the difference between convergent and divergent evolution?
Convergent Evolution
- the evolution of similar traits in distantly related species
- two species are placed under similar selective pressure
Divergent Evolution
-the large-scale evolution of a group into many different forms
List six types of evidence for evolution.
Biogeography
Fossil record
homologous structures
analogous structures
vestigial features and anatomical oddities
recored genetic changes in living organisms
comparing biochemistry and genetics