Unit 2 - Cell organisation and stem cells Flashcards Preview

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Flashcards in Unit 2 - Cell organisation and stem cells Deck (29)
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1
Q

Define cell

A

a single repeating unit of an organism

2
Q

Define tissue

A

a collection of differentiated cells that have a common function

3
Q

Define organ

A

a group of tissues that work together to carry out a common function

4
Q

Define organ system

A

a group of organs that carry out a common function

5
Q

Define specialised

A

having particular structure to serve a particular function

6
Q

Define differentiated

A

the process by which a less specialised cell develops a distinct form and function,a cell specialising

7
Q

Why do multicellular organisms need specialised cells?

A
  • complex communication in a multicellular organism
  • specialised functions need specialised cells
  • maximise efficiency of processes like absorbing nutrients
8
Q

What features does an erythrocyte have to suit it for its function?

A

Biconcave disc- maximises SA to carry oxygen
No nucleus- more room for haemoglobin
Flexible- can squeeze through narrow capillaries

9
Q

What features does a neutrophil have to suit it for its function?

A

Multilobed nucleus- makes it easier for neutrphils to squeeze through small gaps
Granular cytoplasm- contains many lysosomes which contain enzymes used to attack pathogens

10
Q

What features does a root hair cell have to suit its function?

A

Root hairs- increase surface area to maximise uptake of water/minerals from the soil

11
Q

What features does a sperm cell have to suit it for its function?

A

Mitochondria- supplies the energy to swim
Tail- allows for movement
Acrosome- contains digestive enzymes which digest protective layers around ovum

12
Q

What features does a palisade cell have to suit it for its function?

A

Chloroplasts- absorb a large amount of light
Rectangular- packs closely to form a continuous layer
Chloroplasts are able to move in cytoplasm- so can absorb more light

13
Q

What features does a guard cell have to suit it for its function?

A

Cell wall thicker on inside than outside- so cell doesn’t change symmetrically as its volume changes
Gap in the centre- allows gases in and out

14
Q

What are the 4 main categories of tissues in animals?

A

Nerve tissue
epithelial tissue
muscle tissue
connective tissue

15
Q

What are stem cells?

A

Undifferentiated cells with the potential to differentiate into a variety of the specialised cell types of an organism

16
Q

Define undifferentiated

A

An unspecialised cell originating from mitosis or meiosis

17
Q

Define potency

A

the ability of a stem cell to differentiate into different cell types

18
Q

Define totipotent

A

A stem cell that can differentiate into any type of cell (including extra-embryonic) and form a whole organism

19
Q

Define pluripotent

A

a stem cell that can form all types of tissue but not a whole organism

20
Q

Define multipotent

A

can only form a range of cells from a certain cell lineage

21
Q

Give an example of where totipotent cells are found in a human

A

In a zygote

22
Q

Give an example of where pluripotent cells are found in a human

A

Blastocyst

23
Q

Give an example of where multipotent cells are found in a human

A

Blood stem cells

24
Q

What are the characteristics of stem cells?

A
  • can repeatedly undergo cell division
  • not adapted to a specific function
  • can give rise to specialist cells
  • few epigenetic markers
25
Q

What are stem cells used for in the body?

A
  • growth
  • development (of am embryo)
  • tissue repair
26
Q

Where are stem cells found in plants?

A
Vascular cambium
Meristematic tissue (e.g roots and shoots)
27
Q

How do cells become specialised?

A
  • all cells have the same DNA
  • genes are switched on and off by epigenetics
  • different proteins are produced in the cell
  • so the cell can undergo a specialised function due to the proteins
28
Q

How long do erythrocytes live for?

A

120 days

29
Q

How long do neutrophils live for?

A

6 hours