specialised cells and differentiation

Question 1

define the term specialised cell and how does it relate to differentiation

Answer 1

specialised cells are cells that have a unique structure to accommodate their unique function.
they achieve this through the process of differentiation which evolves them to have unique traits.

Question 2

define and describe the function and structure of a red blood cell ( erythrocytes )

Answer 2

function -
transport oxygen around the body
structure -
-» biconcave shape to increase surface area for oxygen absorption
-» no nucleus to maximise space for haemoglobin
-» flexible so it can squeeze through tiny capillaries

Question 3

define and describe the function and structure of nerve cells ( neurons )

Answer 3

function -
transmit electrical signals across the body
structure -
-» long, thin axons to carry signals over long distances
-» dendrites to receive signals from other neurons
-» myelin sheath to insulate axon and speed up transition process

Question 4

define and describe the function and structure of a muscle cell

Answer 4

function -
contract to produce movement
structure -
-» long and fibrous to contract and generate force
-» contains a lot of mitochondria to produce energy for contraction
-» works in a co-ordinated manner for efficient movement

Question 5

define and describe the function and structure of a root hair cell ( in plants )

Answer 5

function -
absorbs water and minerals from soil
structure -
-» long-hair like extension to increase surface area for absorption
-» thin cell wall to allow easy movement of water and minerals

Question 6

define and describe the function and structure of a xylem cell

Answer 6

function -
transport water and dissolved minerals from roots to leaves
structure -
-» hollow tubes with thick walls for strength, formed from dead cells

Question 7

define and describe the function and structure of a phloem cell

Answer 7

function -
transport sugars and nutrients around the plat
structure -
-» sieve plates allow easy flow of sugars
-» companion cells provide energy for the whole process

Question 8

define and describe the function and structure of the egg cell ( ovum )

Answer 8

function -
reproduction as it carries the female genetic material
structure -
-» large cell wall with nutrient-rich cytoplasm to nourish the embryo

Question 9

define and describe the function and structure of the sperm cell

Answer 9

function -
reproduction as it carries the male genetic material
structure -
-» tail ( flagellum ) for swimming for fast movement
-» streamlined head containing genetic material for efficient movement
-» enzymes in the head to break down eggs outer layer and fertilised

Question 10

define why differentiation occurs

Answer 10

cells in multicellular organisms undergo changes in structure and function as it evolves so less specialised cells become specialised ones to accommodate the change

Question 11

describe when differentiation occurs in animals

Answer 11

when cells in the embryo start as stem cells ( undifferentiated cells ) and gradually becomes more specialised as the embryo develops.

Question 12

describe when differentiation occurs in plants

Answer 12

in plant cells, differentiation occurs throughout its life as plant cells are able to retain the ability to differentiate into various cell types, e.g. root, stem and leaf cells.

Question 13

define stem cells

Answer 13

cells that have not yet gone under the differentiation process -» undifferentiated cells

Question 14

define embryonic stem cells

Answer 14

cells that can become any type of cell in the body

Question 15

define an adult stem cell

Answer 15

they are limited and can only differentiate into a smaller range of cell types such as blood or skin cells