Differentiation

Question 0

Totipotent refers to what, in terms of stem cells.

Answer 0

This refers to stem cells which can develop into any type of cell. E.g. Embryonic stem cells

Question 1

What are stem cells

Answer 1

These are cell which are unspecialised. Meaning that they haven’t undergone the process of differentiation.

Question 2

Pluripotent, refers to what, in terms of stem cells?

Answer 2

These are stems cell found in small number in adult tissues. They can develop into but several different cell and are more limited than embryonic stem cells. They can be found in bone marrow.

Question 3

The process by which a cell becomes specialised is know as… What?

Answer 3

Differentiation

Question 4

Info card

-in animals adult cells are used to replace damaged cells e.g. To make new skin or blood.

Answer 4

• stem cells in plants are needed to make new shoots and roots. These stem cells can differentiate into various other tissues such as xylem and phloem.

Question 5

Stems in plants can be found… Where?

Answer 5

In the cambium

Question 6

Info card
- root and stem
The vascular cambium divide and differentiate to become xylem and phloem

Answer 6

• The vascular bundle forms a ring in the roots and shoots.

- cell divide and grow out from ring differentiating as they move away from the cambium.

Question 7

Discuss neutrophils

Answer 7

They are w.b.c e.g. Phagocyte
- they have a flexible shape allowing them to engulf foreign particles or pathogens. The many lysosomes in there cytoplasm contain digestive enzymes helping to break down the engulfed pathogen.

Question 8

Discuss Erythrocytes

Answer 8

R.b.c carrying oxygen around the body.
- The biconcave disc shape provides a large surface area for gas exchange. Having no nucleus creates more space for haemoglobin (the protein which carries oxygen).

Question 9

Discuss epithelial cells

Answer 9

• These cells cover the surface of organs.
• interlocking cell membranes join the cells together, with a membrane at their base.
• In the lungs cilia form on the on the membrane of the epithelial cells
• other like the small intestine have microvilli which increase surface area in the intestine aiding absorption.

Question 10

Discuss sperm cells

Answer 10

• male sex cell
• tail ( flagellum) motor which move on a spiral motion propelling the sperm towards egg cell.
• large amount of mitochondria, providing energy to move.
• at the head of the cell, acrosome containing digestive enzymes to enable it to penetrate the surface of the egg.

Question 11

Discuss palisade mesophyll cells

Answer 11

• in the leaves doing mostly photosynthesis.
• large amount of chloroplast aid with the absorption of sunlight.
• thin walls, allow carbon dioxides easy access via diffusion.

Question 12

Discuss root hair cells

Answer 12

• Absorb water and minerals from soil.
• large surface area and thin walls, with a permeable cell wall, for entry of water and ions
• extra mitochondria for ATP for active transport.

Question 13

Discuss Guard cells

Answer 13

• These cell line the stomata.
• small pore on the surface of the leaf, used in gas exchange.
  In the light:
• they take up water by becoming turgid.
• thin outer walls and thickened inner walls force them to bend outwards opening stomata.