The organisation + specialisation of cells (h,i) Flashcards
1
Q
What are the levels of organisation in a multicellular organism?
A
Specialised cells, tissues, organs, organ systems, whole organism
2
Q
Describe erythrocytes (red blood cells)
A
- transport oxygen around the body
- flattened biconcave disc shape - increases SA:V
- no nuclei - increases space for haemoglobin to carry more oxygen
- flexible - can squeeze through narrow capillaries
3
Q
Describe neutrophils (type of white blood cell)
A
- role in the immune system
- multi-lobed nucleus - makes it easier for them to squeeze through small gaps to get to the site of infection
- granular cytoplasm - contains lysosomes - contains enzymes to attack pathogens
4
Q
Describe sperm cells
A
- delivers genetic information to the female gamete - ovum
- flagellum - to whip + propel the cell
- many mitochondria - for energy to swim
- acrosome - contains digestive enzymes - released to digest protective layers around the ovum - for fertilisation
5
Q
Describe palisade cells
A
- in mesophyll for photosynthesis
- chloroplasts - to absorb large amounts of light
- rectangular shaped - so can be closely packed to form a continuous layer
- thin cell walls - to increase rate of diffusion of CO2
- large vacuole - maintain turgor pressure
- chloroplasts can move within the cytoplasm to absorb more light
6
Q
Describe root hair cells
A
- take up water and minerals from the soil
- present at the surface of roots near the growing tips
- long extensions - root hairs - increase surface area of the cell - to maximise water and mineral uptake
7
Q
Describe guard cells
A
- control gas exchange through stomata, e.g. CO2 for photosynthesis
- when they lose water, they become less swollen and change shape by osmotic forces + close the stoma to prevent further water loss
- cell wall is thicker on one side so the cell does not change shape symmetrically as its volume changes
8
Q
What is a tissue?
A
A tissue is made up of a collection of differentiated cells that have a specialised function or functions on an organism
9
Q
What are the 4 types of animal tissue?
A
- nervous tissue: adapted to support the transmission of electrical impulses
- epithelial tissue: adapted to cover body surfaces, internal and external
- muscle tissue: adapted to contract
- connective tissue: adapted to hold other tissues together, or acts as a transport medium
10
Q
Describe squamous epithelium tissue
A
- made of specialised squamous epithelial cells
- very thin due to squat or flat cells + is only one cell thick - important for when rapid diffusion is needed
- forms the lining of the lungs + allows rapid diffusion of O2 into the blood
11
Q
Describe ciliated tissue
A
- made of ciliated epithelial cells
- cells: have cilia on one surface that move in a rhythmic manner
- lines the trachea to sweep mucus away from the lungs
- goblet cells present release mucus to trap unwanted particles present in the air
12
Q
Describe cartilage
A
- found in the joints, outer ear and nose
- firm flexible tissue compose of chondrocyte cells embedded in an extracellular matrix
- prevents the ends of bones rubbing + causing damage
13
Q
Describe muscle
A
- needs to contract to move bones and the body
- skeletal muscle fibres contain microfibrils which contain contractile proteins
- types of muscle tissue: smooth, skeletal and cardiac
14
Q
What are 2 types of plant tissue?
A
- epidermis tissue: adapted to cover plant surfaces
- vascular tissue - adapted for transport of water + nutrients
15
Q
Describe xylem tissue
A
- vascular tissue for transport of water and mineral ions
- composed of vessel elements - elongated stem cells
- walls of cells are strengthened by a waterproof material called lignin + provides structural support
