Infection and Response

The final section of the GCSE biology summary for B1 covers infectious diseases and the immune system.

Communicable diseases are caused by pathogens, which include:

• Viruses
• Bacteria
• Fungi
• Protists

Vocabulary: Pathogen - A disease-causing microorganism.

Diseases can spread through:

• Direct contact
• Airborne droplets
• Infected water

The human immune system has multiple lines of defense:

1. Physical barriers (skin, mucus membranes)
2. White blood cells (produce antibodies, antitoxins, and perform phagocytosis)

Example: The trachea is lined with mucus and cilia to trap and remove pathogens.

Specific diseases covered include:

• Viral infections: Colds, flu, HIV, measles, tobacco mosaic virus in plants
• Bacterial infections: Salmonella

Highlight: Antibiotics are effective against bacteria but not viruses.

Understanding these topics is essential for students preparing for their GCSE biology exams and forms the foundation for further study in the field.

Cell Transport and Mitosis

This section covers important processes like osmosis, active transport, and cell division, which are essential topics in what is the GCSE biology summary.

Osmosis is the movement of water molecules from a dilute to a concentrated solution through a semi-permeable membrane. Active transport moves ions against the concentration gradient using energy from respiration.

Definition: Active transport - The movement of substances from a low to high concentration using energy from respiration.

The mitosis process explained in B1 biology GCSE involves several stages:

1. DNA replication
2. Chromosome alignment
3. Chromosome separation
4. Cytoplasm division

Highlight: The 3 stages of cell cycle GCSE biology are interphase (growth and DNA replication), mitosis (nuclear division), and cytokinesis (cytoplasm division).

The 4 stages of mitosis are prophase, metaphase, anaphase, and telophase. During this process, what happens to the cell during mitosis is that it divides to produce two identical daughter cells.

Vocabulary: Chromosomes - Long coiled strands of DNA that pair up during mitosis.

Microscopy and Stem Cells

Understanding microscopy techniques and stem cell biology is crucial for what should I revise for biology paper 1.

Microscopes used in biology include:

• Light microscopes: Lower magnification, used for living specimens
• Transmission electron microscopes: High magnification, 2D images
• Scanning electron microscopes: 3D images, lower magnification than TEM

Example: To calculate total magnification: Magnification of eyepiece × Magnification of objective lens

Stem cells are unspecialized cells that can develop into various cell types. There are two main types:

1. Embryonic stem cells: Can develop into any cell type
2. Adult stem cells: Limited to developing into cells from their tissue of origin

Highlight: Stem cells have potential medical applications, such as treating blood disorders and diabetes.