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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Marketing:Introduction

By |2025-02-12T09:34:58+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

ZIMSEC O Level Business Studies Notes: Marketing:Introduction

  • Is the business/organisational function concerned with identifying, anticipating and satisfying consumer needs and wants at a profit
  • The marketing process involves market research to identify consumer needs and wants
  • Once these needs are identified the organisation then satisfied by creating/providing products at the best possible price thus attaining a profit
  • Marketing also […]
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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: Chemicals of Life: Test for Proteins

By |2025-02-12T09:27:39+02:00February 12th, 2025|Notes, O Level Biology Notes, Ordinary Level Notes|

ZIMSEC O Level Biology Notes: Chemicals of Life: Proteins

  • We have already looked at the properties and importance of proteins here
  • Here we will now look at the test for proteins in foods
  • Generally the Biuret’s test is used to test whether proteins are present in food
  • The Biuret’s reagent is made up by adding sodium hydroxide […]
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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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