Molecular Biology and Genetics Fundamentals

Posted by on Jan 17, 2026 in Biology | 0 comments

Cellular Genetics and DNA Structure

Each cell of the body contains 23 pairs of chromosomes—46 in total—with 23 inherited from the mother and 23 from the father. Each chromosome contains genes, which consist of portions of DNA (Deoxyribonucleic acid). DNA is made up of nucleotides, which are the building blocks of both DNA and RNA. Nucleotides contain nitrogenous bases, and the sequence of these bases determines the differences in traits.

DNA exists as a double helix formed by two antiparallel

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Cell Biology Timeline and Eukaryotic Cell Structure

Posted by on Jan 16, 2026 in Biology | 0 comments

Timeline of Key Cell Biology Discoveries

  • 1590 – Hans and Zacharias Janssen built the first microscope.
  • 1665 – Robert Hooke named the cell.
  • 1670 – Anton van Leeuwenhoek designed a simple microscope.
  • 1674 – van Leeuwenhoek discovered animalcules (bacteria and protozoa).
  • 1838 – Schleiden started developing cell theory in plants.
  • 1839 – Theodor Schwann extended cell theory to all animals.
  • 1858 – Rudolf Virchow proved that all cells come from the division of pre-existing cells.
  • 1888 – Santiago
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Biology Exam Revision: Key Concepts in Physiology and Ecology

Posted by on Jan 12, 2026 in Biology | 0 comments

Factors Affecting Photosynthesis Rate

Point: Photosynthesis rate increases as light intensity, $\text{CO}_2$ concentration, and temperature increase—up to an optimum point.

Explanation:

  • Light provides the energy for the light-dependent reactions.
  • $\text{CO}_2$ is a necessary substrate for glucose synthesis (Calvin cycle).
  • Temperature affects the activity of enzymes within the chloroplasts.

Example: In experiments, the rate of oxygen release (or $\text{CO}_2$ uptake) rises with light until a plateau

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Comparative Analysis of Eukaryotic and Prokaryotic Cells

Posted by on Jan 11, 2026 in Biology | 0 comments

11a. Plant, Animal, and Microbial Cells

Plant and animal cells are eukaryotic, featuring a true nucleus and membrane-bound organelles, whereas most microbial (bacterial) cells are prokaryotic, lacking a true nucleus and typical organelles.

Plant cells possess a cellulose cell wall, chloroplasts, a large central vacuole, and plasmodesmata. Animal cells lack a cell wall and chloroplasts but contain lysosomes, centrioles, and a prominent extracellular matrix. Bacterial cells have a peptidoglycan cell

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Human Reproduction: Stages and Systems

Posted by on Jan 10, 2026 in Biology | 0 comments

Human Reproduction Characteristics

Human reproduction is sexual and has two main characteristics:

  • The new individual is formed from a single cell, called a zygote.
  • A zygote originates from the union (fertilization) of two gametes or sex cells.

Humans have two kinds of gametes: sperm and ova. Men produce sperm, and women produce ova.

Puberty

Puberty begins in men with the first ejaculation (spermarche) and in women when the first menstruation takes place (menarche). This process is regulated by Follicle

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Evolution, Speciation and Ecology: Questions & Answers

Posted by on Jan 10, 2026 in Biology | 0 comments

Evolution, Speciation and Ecology Q&A

Fixism and diversity of living things (4 marks)

Question: How does Fixism explain the diversity of living things?

Answer: Fixism claims that species were created as they are now and that they do not change. Therefore, the diversity we find today is the diversity that has always existed.

Convergent evolution: similar wings in birds & butterflies (4 marks)

Question: Explain why two very different species, such as birds and butterflies, can have similar wings

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