1 / 12

INTERMEDIATE 2 BIOLOGY

INTERMEDIATE 2 BIOLOGY. 3 topics: Living Cells, Genetics & Environmental Biology, Animal Physiology Each unit: 1 unit test (NAB) - 45 mins 65% pass mark (only 1 resit) Practical Report: 1 full experimental report Prelim/Exam : 25 MCQ, 65 short answers, 10 essay.

judith-lynn
Télécharger la présentation

INTERMEDIATE 2 BIOLOGY

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. INTERMEDIATE 2 BIOLOGY • 3 topics: Living Cells, Genetics & Environmental Biology, Animal Physiology • Each unit: 1 unit test (NAB) - 45 mins • 65% pass mark (only 1 resit) • Practical Report: 1 full experimental report • Prelim/Exam : 25 MCQ, 65 short answers, 10 essay

  2. Structure & Function of Cells • All cells contain: • Nucleus: • - controls cell activities • - passes on information to next generation • Cytoplasm: • site of biochemical reactions • Cell Membrane: • - controls substances moving in & out of cells

  3. Structure & Function of Cells • Structures only in plant cells: • Chloroplast: • - Contains chlorophyll • - absorbs light to help photosynthesis • Cell Wall: • - made of cellulose, • - keeps cell shape semi-rigid • Vacuole: • - regulates water & solute content

  4. Yeast • - single celled fungus • - doesn’t photosynthesise (no chlorophyll) • - reproduces by budding • - can feed using oxygen • - this is aerobic respiration • - or without oxygen • - this is anaerobic respiration • - respiration is the release of energy from food

  5. Uses of yeast • During anaerobic respiration • - Sugar Alcohol + CO2 + energy • This is known as alcoholic fermentation • In baking • - sugar in dough is fermented to alcohol & CO2 • - bubbles of CO2 makes dough rise • - alcohol is boiled off by the oven

  6. Brewing/Wine making • Beer making uses maltose • Maltose produced by germinating barley grains • Wine making uses sugar from crushed grapes • Alcohol production stops when yeast get poisoned by the alcohol content • Dead yeast must be filtered out

  7. Alternative Fuels • Gasohol • - fuel produced from plant fermentation • - mixture of alcohol and petrol • Biogas • - anaerobic bacteria feed on organic waste • - waste converted to methane (‘biogas’) • - methane is a useful fuel

  8. Antibiotics • A natural chemical produced by micro-organisms • These chemicals can kill or stop the growth of other micro-organisms • If growth is stopped – micro-organism is sensitive to the antibiotic • If it isn’t stopped – it is resistant

  9. Effect of antibiotics on sensitive bacteria • Antibiotics damage bacteria in different ways: • - damage cell membrane • - damage or affect chromosomes • - stop synthesis of cell wall • - stop chemical reactions in cytoplasm • However, many bacteria develop resistance to the antibiotics • Some can develop multiple resistance – e.g. MRSA

  10. Need for a wide range of antibiotics • No one antibiotic is effective against all bacteria • Some people are allergic to certain antibiotics • New resistant strains appear to a particular antibiotic, so others may be needed instead • - in this example 2 antibiotics have no effect

  11. Lactic Acid • Milk is rich in sugar, protein & fat • When milk sours, bacteria feed on the milk • They convert lactose into lactic acid • Lactic acid makes milk proteins clump together (coagulate) • This forms a semi-solid food – yoghurt • The acid conditions (low pH) acts as a preservative

More Related