3.5->3.6 Cell specialisation and Prokaryotic cell

Question 1

Cell specialisation

Answer 1

first group of cells in an embryo are initially identical with same genes needed for it to develop into any one of many different cells
different genes are expressed(switched on) in a cell at any one time for the cell to be specialised, the rest are switched off
as it matures, each cell takes on individual characteristics(shape, number of organelles) to suit a specialised function

Question 2

Tissues

Answer 2

aggregation of similair cells that perform a specific function

Question 3

epithelial tissues

Answer 3

consist of sheets of cells
line the surface of organs
protective of secretory function

e.g.
thin, flat cells that line alveoli(where diffusion takes place)
ciliated epithelium that lines ducts such as trachea(cilia moves mucus over epithelial surface)

Question 4

organs

Answer 4

aggregation of tissues that are coordinated to perform a variety of functions

Question 5

Stomach

Answer 5

muscle to churn and mix stomach contents
epithelium to protect stomach wall and produce secretions
connective tissue to hold together other tissues

Question 6

organ systems

Answer 6

organs grouped together to perform a particular function efficiently

Question 7

digestive system

Answer 7

made up of: salivary glands, oesophagus, stomach, duodenum, ileum, pancreas and liver

Question 8

respiratory system

Answer 8

trachea, bronchi and lungs

Question 9

circulatory system

Answer 9

heart, arteries and veins

Question 10

bacteria adaptation

Answer 10

1. small - 0.1-10 μm in length
2. stores food as glycogen granules and oil droplets
3. can reproduce independently

Question 11

bacteria cell wall

Answer 11

physical barrier that exudes certain substances and protects against mechanical damage and osmotic lysis
made up of murein- polymer of polysaccharides and peptides

Question 12

capsule

Answer 12

mucilaginous slime
protects bacterium from other cells and helps groups of bacteria stick together for further protection

Question 13

cell-surface membrane

Answer 13

differentially permeable layer
controls entry and exit of chemicals
contains cytoplasm which contains 70S ribosomes

Question 14

plasmids

Answer 14

small circular pieces of DNA
can reproduce themselves independently
give bacterium resistance to harmful chemicals e.g. produces enzymes to break down antibiotics
vectors(carry genetic info) in genetic engineering

Question 15

circular DNA

Answer 15

possesses genetic info for replication of cell

Question 16

virus

Answer 16

acellular non-living particles
smaller than bacteria(20-300nm)
can only multiply living inside host

Question 17

flagellum

Answer 17

used for locomotion

Question 18

Capsid in virus

Answer 18

protein coat
encloses nucleic acid e.g. DNA or RNA

Question 19

Lipid envelops in virus

Answer 19

has attachment proteins which allow virus to identify and attach to host cell(if not present, capsid has them)