February 2025

Biology Notes: Water and its properties: Surface tension

By |2025-02-12T09:46:13+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

ZIMSEC O Level Biology Notes:Properties and Biological significance of water

Property: High surface tension and cohesion (adhesion and cohesion)

  • Cohesion is the force whereby individual molecules stick together.
  • Adhesion is the force whereby water molecules stick to other surfaces.

Biological role

  • Cohesion helps water to move as an unbroken column in the xylem tubes in plants.
  • Adhesion helps the water to stick […]
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Biology Notes: Chemicals of Life: Carbohydrates

By |2025-02-12T09:17:28+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

ZIMSEC O Level Biology Notes: Chemicals of Life: Carbohydrates

  • In humans, mammals and a lot of other animals carbohydrates are the body’s main source of energy
  • These may be simple, soluble sugars or complex materials like starch and cellulose
  • But they all  are bio-molecules consisting of carbon (C), hydrogen (H) and oxygen (O)
  • Carbohydrates come in two main types:

    • […]

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Biology Notes: The test for carbohydrates: Starch

By |2025-02-12T09:42:51+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

ZIMSEC O Level Biology Notes: Chemicals of Life: Carbohydrates: Test for Starch

  • We have already looked at the structure, properties and use of carbohydrates here
  • We will now examine the test for starch in foods
  • Remember starch is a polysaccharide which are part of the carbohydrates family
  • Iodine solution is used to test for the presence of […]
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Biology Notes: Chemicals of Life: Test for Carbohydates

By |2025-02-12T09:44:07+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

ZIMSEC O Level Biology Notes: Chemicals of Life: Chemicals of Life: Test for Carbohydrates

  • We have already looked at the structure, properties and use of carbohydrates here
  • We will now examine the test for carbohydrates in food
  • The nature and order of tests carried out depends on whether we are dealing with a reducing sugar or non-reducing […]
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Biology Notes: Chemicals of Life: Proteins

By |2025-02-12T09:26:05+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

ZIMSEC O Level Biology Notes: Chemicals of Life: Proteins

  • Proteins are an essential nutrient to the human body as well as to other animals
  • They are the building blocks of body tissue
  • They also act as a fuel reserve and are used up after carbohydrates and fats stores have been exhausted
  • Proteins are thus very important for […]
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Safety in the laboratory

By |2025-02-12T09:23:30+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

A typical Biology Laboratory. Image credit ad.edu

ZIMSEC O Level Biology Notes: Safety in the Laboratory

A: Eye Protection

 

  • Wear splash goggles all the time.

B: Clothing and Personal Items

  • Closed shoes must be worn during the entire time that you are in the laboratory to protect you from splashes of chemicals, broken glass, […]
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Biology Notes: Emergency Procedures in the Lab

By |2025-02-12T09:24:11+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

Use the available First Aid Kit whenever there is an injury. Image credit MediaWiki

ZIMSEC O Level Biology Notes:Emergency Procedures

  • Immediately alert your instructor in case of ANY accident or fire.

A: Fire

  • In the event that your hair or clothing catches fire — DO NOT RUN. This will fuel the fire. STOP […]
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Biology Notes: Causes of accidents in the laboratory

By |2025-02-12T09:24:33+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

Nitric acid fumes. Image credit amazingrust.com

ZIMSEC O Level Biology Notes:Causes of accidents in the laboratory

  • Fire – There should never be open flames in the lab. Make it a working rule that water is the only nonflammable liquid you are likely to encounter.
  • Explosion – Never heat a closed system or […]
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Biology related careers

By |2025-02-12T09:25:15+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

There are many Biology Related Careers. Image credit corning.com

ZIMSEC O Level Biology Notes:Biology related careers

These fall into the biology of applied sciences such as Agriculture, Medical science, Breeding, Forestry and Horticulture, Fishery, Pest Control and Animal Husbandry. The list is not exhaustive.

  • Medical Doctor
  • Nurse
  • Dermatologist
  • Biological Technician
  • Medical and Health […]
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