Cells and cell membranes

Question 1

resolution of a light microscope

Answer 1

200nm

Question 2

resolution of a TEM

Answer 2

0.1 nm

Question 3

resolution of a SEM

Answer 3

0.1nm

Question 4

magnificent of a light microscope

Answer 4

x1,500

Question 5

magnification of a TEM

Answer 5

x500,000

Question 6

magnification of s SEM

Answer 6

x100,000

Question 7

magnification

Answer 7

the degree to which the size of an image is larger than the object itself

Question 8

resolution

Answer 8

the degree to which it is possible to distinguish between two objects that are very close together

Question 9

explain the need for staining for use in light microscopy and electron microscopy

Answer 9

a lot of biological material inside the cell isn’t coloured, so it might be difficult to distinguish between different features.

coloured stains are used to stain specimens for use with the light microscope.

chemicals which bind to other chemicals in or on the specimen allow the specimen to be seen

some chemicals bind to specific structures e.g. acetic orcein staying dna red

electron micrographs start off B&W with the colour being added by a specialised computer program afterwards.

Question 10

linear magnificent of an image

Answer 10

image size= actually size x magnification

Question 11

nucleus

Answer 11

largest organelle

houses all the cell’s genetic material in the form of DNA, which contains the instructions for protein synthesise.

Question 12

nucleolus

Answer 12

dense spherical structure inside nucleus

makes ribosomes and RNA which pass into the cytoplasm and are used in protein synthesis

Question 13

nuclear envelope

Answer 13

surround the nucleus

double membrane with nuclear pores

Question 14

SER and RER

Answer 14

continuous with the nuclear envelope. RER is studded with ribosomes, SER is not

transports proteins made by the attached ribosomes
SER involved in making lipids

Question 15

golgi apparatus

Answer 15

stack of membrane bound flattened stacks

modifies proteins received from the rough ER and then packages them into vesicles so they can be transported

Question 16

ribosomes

Answer 16

tiny some are in cytoplasm some are bound to RER

site of protein synthesis

Question 17

mitochondria

Answer 17

spherical or sausage shaped double membrane

where ATP is made during aerobic respiration

Question 18

lysosomes

Answer 18

spherical sacs single membrane

contain digestive enzymes that are used to break down materials by catabolism

Question 19

chloroplasts

Answer 19

only in plant cells, two membranes contain thlakoids

site of photosynthesus

Question 20

centrioles

Answer 20

small tubes of protein fibres- pair of them next to nucleus in animal cells

form the spindle which moves chromosomes during cell division

Question 21

flagella and cillia

Answer 21

hair like extensions projecting from the surface of a cell

move by ATP e.g. wave mucus along trachea or make sperm swim

Question 22

outline the interelationship between the organelles involved in the production and secretion of proteins

Answer 22

• the gene containing the instructions for the production of the hormones is copied on to a piece of mRNA
• mRNA leaves the nucleus through a nuclear pore
• mRNA attaches to a ribosome
• ribosome read the instruction to assemble the protein
  molecules are ‘pinched off’ in vesicles and travel towards the golgi apparatus
• vesicles fuse with the golgi apparatus
• gogli apparatus processes and packages the molecules for release
• the molecules are ‘pinched off’ in vesicles from the golgi app and move towards the cell surface membrane
• vesicles five with the cell membrane
• cell surface membrane opens to release molecules outside.

Question 23

exoskeleton- made of ?

Answer 23

cytoplasm contains 2 types of protein fibres: microfilaments (small solid strands made of actin 7nm diameter) and microtubules (protein cylinders made of tubulin molecules, 25nm diameter).

Question 24

functions of exosketelon

Answer 24

supporting organelles
strengthening the cell and maintaining cell shape
transporting materials within the cell )e.g spindle during mitosis)

Question 25

compare and contrast, with the aid of diagrams and electron micrographs, the structure of prokaryotic cells and eukaryotic cells

Answer 25

prokary- no nucleus - they are bacteria and much smaller than eukaryotes
they have:
one membrane 
no membrane bound organelles
cell made made of peptidoglycan 
circular dna 
dna not surrounded by membrane
ATP production takes place in specialised infolded regions of the cell surface membrane 
some have flagella

Question 26

compare and contrast, with the aid of diagrams and electron micrographs, the structure of plant cells and animal cells

Answer 26

plants cells have a cell wall- outside cSM made of cellulose which forms a sieve link network of strands which make the cell wall v strong
this is kept rigid by the pressure of the fluid inside the cell (vacuole) so supports the cell and therefore the entire plant
plants cells also contains a vacuole- that maintains cell stability by making the cell turgid as it increases the pressure inside the cell this in turn also helps support the plant.