6.5 Stem cells

Question 1

Stem cells are …

Answer 1

• undifferentiated cells which are genetically identical and have the ability to develop into any of the various kinds of cells

Question 2

What are the uses of stem cells?

Answer 2

• in research and medicine
• for instance repair of damaged tissues, treatment of neurological disorders such
  as Parkinson’s and Alzheimer’s as well as studying development

Question 3

What is the process in which a cell specialised to carry out particular functions?

Answer 3

• differentiation

Question 4

Where are stem cells found?

Answer 4

• in bone marrow where they differentiate into erythrocytes (red blood cells) and neutrophils (white blood cells)

Question 5

Role of erythrocytes is …

Answer 5

• transporting oxygen into the blood
• short lived as they are constantly destroyed and created

Question 6

Role of neutrophils is …

Answer 6

• involved in attacking and
  destroying foreign microorganisms in the process of phagocytosis

Question 7

Where does plants differentiate?

Answer 7

• plants retain their ability to differentiate into different types of cells throughout their life

Question 8

How does division in plants occur?

Answer 8

• at high rates in meristems

Question 9

What are dividing meristems known as and what do they do?

Answer 9

• cambium
• give rise to xylem and phloem tissue

Question 10

Sperm cells are …

Answer 10

• male gametes, made in the testes throughout a man’s life, they are adapted to reach, penetrate and fertilise the ovum i.e. the female gamete

Question 11

Palisade cells are …

Answer 11

• most basic plant cell type, contain many chloroplasts and are specialised for photosynthesis

Question 12

Root hair cells are …

Answer 12

• specialised epidermal cells found in close proximity to root tips
• they have thin and long extensions which serve for the purpose of increasing surface area and maximising the contact with water which contains essential
  mineral ions which are absorbed through the roots
• they are short-lived and are
  constantly produced in the root tip

Question 13

Guard cells are …

Answer 13

• found in pairs in the epidermis of leaves and are involved in
  controlling the opening and closing of stomata
• they contain chloroplasts
  whereas epidermal cells do not
• they respond to water influx which causes them to
  alter their shape, causing stoma to open