Cell specialisation and stem cells Flashcards Preview

A level Biology xoyzq > Cell specialisation and stem cells > Flashcards

Flashcards in Cell specialisation and stem cells Deck (18)
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1
Q

differentiated

A

specialised to carry out a function

2
Q

specialisations of erythrocytes (3)

A
  • flattened biconcave shape increasing SA:Vol ratio
  • no nuclei or many other nuclei to max space for Hb
  • flexible so can squeeze through narrow capillaries
3
Q

specialisations of neutrophils (2)

A
  • multi-lobed nucleus so easier to squeeze through small gaps to get to site of infection
  • granular cytoplasm contains many lysosomes with enzymes used to digest pathogens
4
Q

specialisations of sperm cells (3)

A
  • tail/ flagellum so can move
  • many mitochondria to supply energy to swim
  • acrosome at head contains digestive enzymes to digest protective layer around ovum and allow sperm to penetrate and fertilise the egg
5
Q

specialisations of palisade cells (4)

A
  • many chloroplasts to absorb light for photo
  • rectangular box shaped so can be closely packed
  • thin cell walls to increase r.o.diffusionof CO2
  • chloroplasts can move within cytoplasm to absorb more light
6
Q

specialisations of root hair cells (1)

A
  • have root hairs which increase SA to maximise uptake of water and minerals from soil
7
Q

specialisations of guard cells (2)

A
  • when they lose water they become flaccid and stomata close to prevent further loss of water
  • cell wall thicker on one side so cell does not change shape symmetrically as its volume changes
8
Q

specialisations of squamous epithelium (1)

A
  • made up of very thin epithelial cells which allow rapid diffusion across the surface. (essential as forms lining of lungs and allows rapid diffusion of O2 into blood)
9
Q

specialisations of ciliated epithelium (2)

A
  • cilia move in rhythmic manner and sweep mucus away from the lungs in trachea
  • goblet cells release mucus which trap dust and dirt particles (pathogens)
10
Q

specialisations of cartilage (connective tissue found in outer ear, nose, and between bones. Contains elastin and collagen)

A
  • chondrocyte cells embedded in extracellular matrix. Prevents bones rubbing together and causing damage.
    Firm flexible connective tissue
11
Q

specialisations of muscle

A

skeletal muscle fibres contain myofibrils which contain contractile proteins that allow the muscle to contract (shorten) and move bone

12
Q

specialisations of epidermis tissue

A
  • covered by waxy cuticle to reduce water loss

- contains stomata which can open and close to allow CO2, O2 and water vapour in and out

13
Q

specialisations of xylem tissue

A
  • elongated dead vessel elements allow water and minerals to travel up in continuous stream
  • xylem walls strengthened with waterproof lignin, which provides the plant with structural support
14
Q

specialisations of phloem tissue

A
  • sieve tube elements perforated by sieve plates

- companion cells are very metabolically active and provide phloem with necessary support

15
Q

potency

A

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

16
Q

totipotent

A

stem cells that can different into any type of cell

  • fertilised egg (zygote)
  • 8 or 16 cells from first few mitotic divisions
17
Q

pluripotent

A

stem cells that can form all tissue types but not whole organisms
- early embryos

18
Q

multipotent

A

stem cells that can only form a range of cells within a certain type of tissue
- haematopoetic stem cells in bone marrow can make different types of blood cell