Cell Specialisation

Question 1

Define differentiation

Answer 1

refers to changes occurring in cells of a multicellular organism so that each different type of cell becomes specialised to perform a specific function

Question 2

Why do multicellular organisms need specialised cells?

Answer 2

Smaller SA-VOL ratio and not all cells are in contact with the external medium, specialised cells form tissues and organs to carry out functions

Question 3

In what 3 ways can cells differentiate?

Answer 3

change numbers of an organelle, change shape of cell, change some contents of cell

Question 4

What are the name for red and white blood cells?

Answer 4

Red: erythrocytes, type of white: neutrophils

Question 5

What happens to stem cells that will become erythrocytes?

Answer 5

lose their nucleus, mitochondria, Golgi and RER, packed full of protein: haemoglobin, shape to biconcave discs

Question 6

What happens to stem cells that will become neutrophils?

Answer 6

Keep nucleus, lots of lysosomes produced to kill micro-organisms with digestive enzymes

Question 7

4 ways that sperm cells are specialised?

Answer 7

many mitochondria, sperm head contains specialised lysosome (acrosome), small long and thin shape, single long undulipodium

Question 8

Define tissues, 4 examples

Answer 8

A collection of similar cells performing a common function, may be attached to each other e.g. xylem and phloem, epithelial and nervous tissue

Question 9

Define organ, 2 examples

Answer 9

Collection of tissues working together to perform a function, e.g. leaves or liver

Question 10

Define organ system, 2 examples

Answer 10

Made of a number of organs to perform an overall life function, e.g. excretory and reproductive systems