Peer Teaching - Biology

Peer Teaching - Biology

Grade 8th

Transport in Animals

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Compare this 2 circulatory systems

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Multiple Choice

Mammals have a double circulatory system. This means that

• Oxygenated blood passes twice through the heart.

• Deoxygenated blood passes twice through the heart.

• Blood passes through the heart twice in every one circulation around the body.

• A mixture of oxygenated and deoxygenated blood is pumped out of heart to the rest of body.

Open Ended

What are the benefits of double circulation? 

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Multiple Choice

The fluid portion of blood that carries blood cells, glucose, proteins, fats, and wastes throughout the body.

• red blood cells
• white blood cells
• plasma
• platelets

Open Ended

State the adaptation of RBC related to its function

Open Ended

State the function of platelets

Open Ended

Coronary arteries disease caused by deposit of ______

​Heart rate

​The heart rate is the number of times the heart beats in the space of a minute.

​Calculation

​1 small box = 40 ms

​From R to R = 20 small boxes

​1 beat = 20 small boxes x 40 ms

​1 beat = 800 ms = 0.8 s

​Beat per minute = 60 s : 0.8 s = 75 beat / min

​Pathogen and Immunity

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​Pathogen

• ​A pathogen​A pathogen is a disease-causing organism

• Pathogens are passed on from one host to another and therefore the diseases they cause are known as transmissible disease is a disease-causing organism

​Body Defences

​I. Mechanical barrier

​ - Skin: has thick outer layer of dead cells that is very difficult to penetrate

​Body Defences

​I. Mechanical barrier

​​ - Nostrils Hairs: to trap dust that might be carrying pathogens

​ - Cilia: trap the pathogens then sweep the mucus back to throat

​Body Defences

II. Chemical barrier

• Enzymes in tears, saliva and mucus: break down the surface of bacteria.

• Acid in sweat and in the stomach: kills cellular pathogens

​Body Defences

III. Cell

• Cells – different types of white blood cell work to prevent pathogens reaching areas of the body they can replicate in

  • By phagocytosis – engulfing and digesting pathogenic cells

​Body Defences

III. Cell

• ​By producing antibodies - which clump pathogenic cells together so they can’t move as easily (known as agglutination) and releasing chemicals that signal to other cells that they must be destroyed

Lymphocytes

Type of white blood cell (leukocyte) that is of fundamental importance in the immune system because lymphocytes are the cells that determine the specificity of the immune response to infectious microorganisms and other foreign substances.

Antibody and Antigen

• ​All cells have proteins and other substances projecting from their cell membrane. These are known as antigens and are specific to that type of cell

• Lymphocytes have the ability to ‘read’ the antigens on the surfaces of cells and recognise any that are foreign

• They then make antibodies which are a complementary shape to the antigens on the surface of the pathogenic cell

Lymphocyte - Antibody - Antigen

Multiple Choice

What is the function of phagocytes?

• Transport oxygen around the body

• Engulf and digest pathogens

• Produce antibodies which destroy pathogens

• Clot together to prevent bleeding

Multiple Choice

What attaches to antigens and tags the pathogen for destruction?

• Pathogen

• Antibodies

• B-cells

• Lymphocyte

Multiple Choice

What is the function of lymphocytes?

• Transport oxygen around the body

• Engulf and digest pathogens

• Produce antibodies which destroy pathogens

• Clot together to prevent bleeding

Open Ended

What is antigen?

​Infection and Memory Cells

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Passive and Active Immunity

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Multiple Choice

Weakened microbes that stimulate the immune system to produce antibodies used to fight future invasions by the same microbe. Example: chicken pox, measles, small pox

• Vaccine

• Disease

• Immunity

Multiple Choice

Which is an example of passive immunity?

• people being vaccinated against disease
• people taking vitamins to boost their immune response
• people receiving antibodies from their mothers before birth
• people producing antibodies against organisms that cause diseases they have had previosuly

Multiple Choice

A secondary immune response will be faster when...

• The individual has encountered the pathogen already
• The individual's macrophages are on high alert
• The individual has encountered the pathogen and has memory B cells circulating
• All of the above

Open Ended

State one major advantage passive immunity and active immunity