cell specialisation

Question 1

what is tissue

Answer 1

A tissue is a collection of differentiated similar cells that have Specialist functions

Question 2

Main animal tissues

Answer 2

Nervous tissue
epithelial tissue
muscle tissues
connective tissues

Question 3

Main plant tissue

Answer 3

epidermal tissue
vascular tissue

Question 4

What is an organ And give examples

Answer 4

An organ is a collection of tissue that are adapted to carry out a particular function
e.g. heart, lungs, leaf

Question 5

What is an organ system

Answer 5

Interconnected organs to carry out major functions of organism like digestive system or cardiovascular system

Question 6

in humans where are stem cells found

Answer 6

Early embryos, most in bone marrow, some everywhere, Umbilical cord

Question 7

Where are stem cells found in plants

Answer 7

meristem (Root tips and shoot tips)

Question 8

What are erythocytes cells

Answer 8

• Red blood cells which have a flattened biconcave shape which increases their surface area to volume ratio which is essential to the role of transporting oxygen around the body
• they don’t have a nuclei or many other organelles which increases space available for haemoglobin (molecule that binds to oxygen)
• they are very flexible so they are able to squeeze through the narrow capillaries

Question 9

What are neutrophils cells

Answer 9

• Type of white blood cells that play a role in the immune system
• they have multi lobed nucleus which makes it easier for them to squeeze through small gaps to get to sites of infections
• the granular cytoplasm contains many lysosomes that contains digestive enzymes to attack pathogens

Question 10

What are Sperm cells

Answer 10

• Male gametes that deliver genetic information to the female gamete
• sperm have a tail or flagellum so they are able to move/ swim
• they contain many mitochondria to supply energy needed to move/spin
• the acrosome on the head contains Digestive enzymes which are released to digest the protective layers around the egg and allow the sperm to penetrate leading to fertilisation

Question 11

what is the Squamous epithelium tissue

Answer 11

• Made up of squamous epithelial cells and known as pavement epithelium due to flat appearance
• it is very thin because there’s one cell thick
• Present where rapid diffusion across the surface is essential
• e.g. forms the lining of the lungs and allows rapid diffusion of oxygen into the blood

Question 12

What is the ciliated epithelium tissue

Answer 12

• Made up of ciliated epithelial cells
• the cells have hair like structures called cilia on one surface
• it lines the trachea causing mucus to be swept away from the lungs
• goblet cells are also present releasing mucus to trap any unwanted particles in the air which prevents the particles (may be bacteria) from reaching the Alveoli

Question 13

What is cartilage tissue

Answer 13

• Connective tissue found in outer ear nose and between bones
• contains fibres of the protein; elastin and collagen
• its firm and flexible
• composed of chondrocyte cells embedded in an extracellular matrix cartilage Which contains elastin
• prevents the ends of burns from rubbing together and causing damage

Question 14

What is muscle tissue

Answer 14

• Muscle tissue needs to be able to shorten in length in order to move bones which in turn moves the different parts of the body
• there are different types of muscle fibres; skeletal muscle fibres (muscles which are attached to the bone) contain myofibrils which contain contractile proteins

Question 15

what are palisade cells

Answer 15

• Present in plant mesophyll
• contain chloroplasts Which can move within the cytoplasm to absorb large amounts of sunlight for photosynthesis
• can be closely packed to form a continuous layer
• have thin sell walls increasing rate of diffusion of carbon dioxide
• large vacuole to maintain turgor pressure

Question 16

What are root hair cells

Answer 16

• Present at the surfaces of roots near the growing tips
• are long and thin which increases surface area And allows for faster uptake of water and minerals from soil

Question 17

What are guard cells

Answer 17

• Pairs of cells on the surface of leaves forming small openings called stomata
• Allows water vapour and oxygen in and out
• necessary for carbon dioxide to enter plants for photosynthesis
• When guard cells loose water and become less swollen, they change shape and stoma closes to prevent further water loss

Question 18

What is the epidermis tissue

Answer 18

• A single layer of closely packed cells covering the surface of plants
• Covered by waxy waterproof cuticle to reduce the loss of water
• guard sells a present in the epidermis allowing carbon dioxide in and out and water vapour and oxygen in and out

Question 19

What is the xylem tissue

Answer 19

• a type of vascular tissue responsible for the transport of water and minerals throughout the plant
• Composed of vessel element which are elongated dead cells
• The walls of these cells are strengthened with a waterproof material called lignin providing structural support for plants

Question 20

What is the phloem tissue

Answer 20

• Another type of vascular tissue responsible for transport of organic nutrients (particularly sucrose) from leaves and stems (where it is made by photosynthesis) to all parts of the plant where it is needed
• Composed of columns of sieve tube cells separated by perforated walls called sieve plates

Question 21

What does Totipotent mean

Answer 21

stem Cells that can differentiate into any type of cell

Question 22

What does pluripotent mean

Answer 22

stem cells that can differentiate into any type of human body cell

Question 23

What does multipotent mean

Answer 23

stem Cells that can differentiate into some types of human cells

Question 24

What does unipotent mean

Answer 24

stem Cells that can only differentiate into one type of cell

Question 25

What are the two properties of stem cells?

Answer 25

They keep dividing and they can differentiate to a specialised cell.

Question 26

What is cell therapy.

Answer 26

viable Cells injected grafted implanted into a patient

Question 27

Get three possible uses of stem cells.

Answer 27

Growth repair research.

Question 28

What is cell programming?

Answer 28

Changing with the cell does. by changing it back to a stem cell and then differentiating it.

Question 29

What is therapeutic cloning.

Answer 29

Cloning an embryo for stem cells.

Question 30

What is direct trans differentiation/ reprogramming?

Answer 30

Turning one specialised cell into another specialised cell without the stem cell step.

Question 31

What is gene therapy?

Answer 31

Editing a mutation/genes

Question 32

What are advantages and disadvantages of using embryonic stem cells for medical research?

Answer 32

Advantages;
We use embryos that would have been wasted, It would help the curing of disease, improves quality of life.
Disadvantages;
Not ethical, religious objections, are later on destroyed.

Question 33

How stem cells are used in medicine?

Answer 33

If heart cells are damaged, body is unable to sufficiently replace the damaged cells.
With Alzheimer’s. nerve cells in the brain die resulting in memory loss. Stem cells could be used to regrow healthy nerve cells.
Patients with Parkinson’s face Uncontrollable tremors Due to a loss of certain type of brain’s nerve cell Which releases a chemical called dopamine, which is needed to control movement. transplanted stem cells can help to regenerate the dopamine producing cells.