B2.3 Cell Specialisation

Question 1

what are the properties of stem cells

Answer 1

• divides indefinitely to create more
• no limit to times it can divide
• differentiates to become a specialised cell

Question 2

differentiation

Answer 2

development of specialised structures and functions in cells

Question 3

what are stem cells

Answer 3

undifferentiated cell in embryo or adults that can undergo unlimited division and can give rise to one of many different cell types

Question 4

when does differentiation occur

Answer 4

when different cell types express different genes

Question 5

gene expression

Answer 5

information encoded in a gene is turned into a function

protein translation - sequence of a dna is transcribed to form RNA

Question 6

Some of the tissues which retain stem cells within a niche

Answer 6

bone marrow
hair follicles

Question 7

bone marrow niche

Answer 7

• niche for stem cells which are used to replace rbc, abc and platelets
• important for continual production of cells - required indefinitely

Question 8

hair follicle niche

Answer 8

• located at the root of the hair where the hair is anchored into the skin
• Stem cells here promote continual hair growth

Question 9

what should the environment provided by the niche cells have

Answer 9

• The ability to maintain an inactive state of the stem cells
• The ability to stimulate stem cell proliferation and differentiation

Question 10

where have stem cell niches been found

Answer 10

brain, bone marrow, skeletal muscle, skin, teeth, heart, intestines, liver, etc.

Question 11

what are stem cell niches

Answer 11

locations within the tissues where stem cells reside and recieve physical and chemical signals

Question 12

potency

Answer 12

The ability of stem cells to differentiate into more specialised cell types

Question 13

Totipotency

Answer 13

entirely potential

capable of giving rise to any cell type in an organism, including making more totipotent stem cells and making the cells that become the placenta

Question 14

example of totipotent cell

Answer 14

zygote - can become any body cell

Question 15

Pluripotency

Answer 15

many potentials

able to develop into many different types of cells or tissues in the body, except for becoming placental cells or totipotent

Question 16

example of Pluripotency

Answer 16

inner cell mass of a embryo

can become anything except placenta

Question 17

Multipotency

Answer 17

multiple potentials

can create, maintain and repair the cells of one particular organ tissue

partially differentiated but can still become multiple cell types

Question 18

example of Multipotency

Answer 18

adult stem cells

bone marrow stem cells differentiate into different blood cells

Question 19

Unipotency

Answer 19

unipotent stem cells are adult cells that can only differentiate into their own lineage

Most cells in animal bodies are unipotent

Question 20

example of Unipotency

Answer 20

heart muscle cells (cardiomyocytes) can generate new cardiomyocytes through the cell cycle to build and replace heart muscle.

Question 21

fertilisation

Answer 21

multstep process in which a sperm and egg fuse to form zygote

sexual reproduction

Question 22

zygote - embryo

Answer 22

zygote divides through mitosis to form an embryo which are genetically identical cells

Question 23

nucleus of zygote

Answer 23

is diploid
2 sets of chromosomes

Question 24

morphogens

Answer 24

A morphogen is defined as signaling molecules

act over long distances to induce responses in cells based on the concentration of morphogen that the cells interact with.

Question 25

cell specialisation

Answer 25

allows cells to perform a function with increase efficiency

Question 26

embryonic stem cells

Answer 26

undifferentiated cell in early stage embryo, capable of continual cell division and of developing into all the cell types of an adult organisation

Question 27

specific of adaptation of stem cells

Answer 27

cells can develop into specific shapes and sizes cells can create protiens needed to carry out specific metabolic reactions

Question 28

Red blood cells

Answer 28

are small to allow movement through narrow capillaries

Question 29

human sperm cell size and structure

Answer 29

long and narrow cells with a strong flagellum for movement

Question 30

human sperm benefits

Answer 30

adapted to reduce resistance as the cell moves towards the egg

Question 31

human egg cell size and structure

Answer 31

large and spherical - largest of any human cell

Question 32

human egg cell function

Answer 32

stores all of the nutrients and materials needed for initial development of embryo

Question 33

neurone cell size

Answer 33

large cell body with long narrow axon that can extend for a meter or more

Question 34

neurone cell function

Answer 34

rapid transmission and information along the distance

Question 35

striated muscle fibre cell size and structure

Answer 35

long, narrow, cylindrical shaped cells

Question 36

striated muscle fibre cell function

Answer 36

generates force and contracts in order to cause movement

Question 37

surface area to volume ratio

Answer 37

As cells increase in size their surface area to volume ratio (SA:V) decreases as there is less surface area in relation to the volume of the organism