cells

Question 1

what is the structure and function of the vacuole?

Answer 1

structure - membrane (tonoplast) bound sac.
functions - stores sugars, water and ions. For support makes the cell rigid.

Question 2

what is the structure and function of the ribosomes?

Answer 2

structure - small cytoplasmic granules
functions - site of protein synthesis
adaptations - eukaryotes around 25nm (80s) prokaryotes which are smaller (70s)

Question 3

what is the structure and function of the cell membrane?

Answer 3

structure - semi permeable has proteins and lipids
functions - controls enter and exit to the cell

Question 4

what is the structure and function of the nucleus?

Answer 4

structure - contains hereditary material e.g DNA and has 10mm to 20mm diameter, envelope bound.
function - controls centre of the cell and hold genetic material.
adaptations - large molecules can exit through the pores.

Question 5

what is the structure and function of the mitochondria?

Answer 5

structure - double membrane bound, inner membrane folded into cristae.
functions - aerobic respiration
adaptations - large internal membrane surface area for respiratory reactions.

Question 6

what is the structure and function of the chloroplasts?

Answer 6

structure - double membrane bound, Thylakloid membrane and stroma where it occurs.
function - photosynthesis
adaptation - large surface area.

Question 7

what is the structure and function of the Golgi apparatus?

Answer 7

structure - stacks of membrane, flattened stacks. associated with vesicles.
function - add carbohydrates to proteins to form glycoproteins. Package enzymes

Question 8

what is the structure and function of the endoplasmic reticulum?

Answer 8

structure - network of tubules ( cisternae)
function - stores and transports carbohydrates & lipids

Question 9

what is the structure and function of the lysosomes?

Answer 9

structure - spherical sacs, 1 membrane
function - breakdown materials using digestive enzymes

Question 10

what is the structure and function of the cell wall?

Answer 10

structure - cellulose myofibrils
function - provides strength and support for the cell with rigid structure.

Question 11

organelles involved in protein synthesis (steps)

Answer 11

• ribosomes are made in the nucleus
• most ribosomes leave the nucleus through the nuclear pores and adhere to the RER
• a mRNA copy of the gene is made in the nucleus
• the mRNA leaves through a nuclear pore and enters the cytoplasm
  the mRNA reaches a ribosomes and is translated to create a polypeptide chain
• the newly formed protein is fed into the RER and transported through the cell
• the protein reaches the golgi apparatus and is labelled with the carbohydrate.
• the protein is transported in a vesicle to where it is needed in the cell and then released.

Question 12

light microscope (to compare with electron)

Answer 12

• light is the illuminating source
• specimen preparations takes few mins to an hour and can be live or dead
• condenser, objective and eye piece lenses are made from glass
• specimen is stained by coloured eye
• it has low resolving power (0.25um - 0.3um). it has magnification of 500x to 1500x
• image is seen by eye through lens

Question 13

electron microscope (to compare with light)

Answer 13

• the beam of electrons is the electron source
• specimen preparations usually take a few days, only dead or dried specimens can be used
• all lenses are electromagnetic
• specimen is coated in metals in order to reflect electrons
• it has a revolving power (0.001um) about 250 times higher than light. it has a magnification more than 100000x
• image is produced on the fluorescent screen or photographic plate.

Question 14

standard deviation

Answer 14

X is change in mass
_
X is mean change
n is number of participants