Cells and microscopy

Question 1

transmission electron microscope

Answer 1

use a beam of electrons passing through a sample which is detected and used to produce the image.

Question 2

scanning electron microscope

Answer 2

uses beam of electrons which is passed across the surface of a specimen. electrons are knocked off the specimen and detected in order to produce an image.

Question 3

light microscope advantages

Answer 3

can look at live specimens
samples can be seen in natural colour
portable
easy to use
inexpensive

Question 4

electron microscope advantages

Answer 4

see up to 0.2 nanometres
greater magnification
greater resolution
can produce 3D images

Question 5

light microscope disadvantages

Answer 5

can’t see below 200 nanometres
lower magnification
lower resolution
only 2D images

Question 6

electron microscope disadvantages

Answer 6

expensive
large
specimen are dead
not portable
samples only seen in black and white
need special training to use them

Question 7

magnification

Answer 7

how many times larger the image is compared to the actual object

Question 8

resolution

Answer 8

is the minimum distance at which two sperate objects appear as separate images

Question 9

magnification formula?

Answer 9

magnification = image size/object size

Question 10

nucleus

Answer 10

contains DNA, associated with histone proteins and forms chromatin, controls the cells activities

Question 11

nucleolus

Answer 11

involved in synthesis and assembly of ribosomes

Question 12

nuclear envelope

Answer 12

double membrane with pores, pores allow large molecules to pass in/out of the nucleus, outer membrane continuous with RER and often has ribosomes on surface

Question 13

RER

Answer 13

has ribosomes on it’s surface, function is protein synthesis

Question 14

SER

Answer 14

site of lipid and steroid synthesis and processing

Question 15

golgi apparatus

Answer 15

series of flattened vesicles in stacks which takes proteins and modifies them/process/package them. secretory vesicles transport proteins

Question 16

ribosomes

Answer 16

involved in protein synthesis, free or bound to RER, made of protein and RNA, made of two subunits (large and small subunit)

Question 17

mitochondria

Answer 17

double membrane, inner membrane folded into cristae, proteins attached to surface, inside is the matrix - contains enzymes of respiration, site of aerobic respiration, ATP produced, has it’s own DNA

Question 18

chloroplasts

Answer 18

site of photosynthesis, double membrane, contains a series of stacked membranes

Question 19

plasma membrane

Answer 19

regulates entry of molecules

Question 20

centrioles

Answer 20

small hollow cylinders, contains rings of microtubules, separation of chromosomes, cell division, found in pairs at right angles (9 triplets, 27 in total)

Question 21

cell wall

Answer 21

rigid structure surrounding a plant cell, made of cellulose, maintains turgidity

Question 22

flagella

Answer 22

like cilia but longer, microtubules contract to make flagellum move

Question 23

cilia

Answer 23

small and hairlike, found on surface of the membrane, able to move substances along the cell surface

Question 24

cytoskeleton

Answer 24

network of 4 different protein threads, cytoskeleton supports cell organelles and keeps them in position, assists in transporting materials and organelles around the cell, provides mechanical strength