Multicellular Organisms - The Blood

Question 1

What does the blood contain and what does it transport?

Answer 1

• Contains plasma, red blood cells and white blood cells
• Transports oxygen (oxyhaemoglobin), nutrients (e.g. glucose, amino acids) and carbon dioxide.

Question 2

Describe the role and features of the RBCs

RBC = Red Blood Cells

Answer 2

Role: Specialised to carry oxygen
Features:
- contains large quantities of haemoglobin - binds to oxygen
- no nucleus - saves space for more haemoglobin
- biconcave disc shape - increases surface area of the cell mem. for the oxygen to diffuse across
- tiny and flexible - letting them squeeze through the narrow capillaries to deliver oxygen

Question 3

Describe the roles and features of the WBCs

WBC = White Blood Cells

Answer 3

Role: Involved in destroying pathogens (disease-causing microorganisms) as part of the immune system
* 2 main types - Lymphocytes and Phagocytes

Question 4

Describe the process of Phagocytosis

Answer 4

PROCESS
* Phagocyte captures the pathogen by flowing its cell membrane around it
* Pathogen is engulfed into the vacuole of the phagocyte
* Pathogen is digested using enzymes

Question 5

What do lymphocytes produce and how does this help to destroy pathogens?

Answer 5

• They produce antibodies that neutralise and destroy invading cells
• Antibodies produced are specific to one type of pathogen. The antibody binds to the pathogen, preventing it from invading.

Question 6

What is the word equation for the transport of oxygen through the RBCs?

Answer 6

oxygen + haemoglobin ⇌ oxyhaemoglobin
* this is reversible as oxygen is released at locations in the body that lack oxygen