Cell Structure and microscopes

Question 1

microscope images

Answer 1

.laser scanning confocal microscope:
.200nm res
.2D/3D
.coloured

SEM:
.10nm res
.3D
.shows cell surface
.black and white

TEM:
.0.5nm res
.x500,000
.2D
.shows interior of cell
.black and white

Light:
.200nm res
.x1500
.2D
.colour

Question 2

drawing

Answer 2

.use sharp pencil
.no shading/cross hatches
.add scale/ magnification
.add title

Question 3

slide preparation improvements

Answer 3

.place stain at the edge of sample
.lower cover slip at an angle using a mounting needle
.use blotting paper to remove excess stain
.use more than one stain

Question 4

evidence that an electron microscope was used instead of a light

Answer 4

.organelles are seen in more detail
.golgi,mito,ER and ribo can be seen
.resolution is better

Question 5

laser scanning confocal microscope compared to electron

Answer 5

LSCM:
.lower res
.has fluorescent tag
.can see movement(living cells)
.can see diff layers

Question 6

difference between SEM and TEM

Answer 6

SEM:
.shows surface view
.in 3D
.better res

Question 7

uses of microscope

Answer 7

.light- looking at whole cells and tissues

TEM-looking ar organelles

laser scanning- an object at a certain depth within a cell

Question 8

how to measure diameter of things through a light microscope

Answer 8

.use eyepiece graticule
.calibrate garticule using stage micrometer
.measure diameter of object in epu
.take repeat measurements and calculate mean diameter
.used calibrated epu to calculate diameter in um

Question 9

improvement to creating a slide for microscope

Answer 9

.sharp blade should be used
.so slide is thin enough and individual cells are visible

.give a method for slicing the tissue thinly so slide is thin enough and individual cells are visible

.select the thinest slides to ensure maximum light can penetrate the sample

.use wet mount to prevent dehydration of tissue

.squash slide so it is easier to see indivivdual cells

Question 10

why use differential stains

Answer 10

.to identify differences between cells
.to identify differences between organelles
.allows cells that cannot be seen be seen like white blood cells
.increases contrast

Question 11

why do some cytoplasms apear different under microscope when stainned

Answer 11

.blue/purple due to having more nucleic acid
.so has RNA

.red due to having more protein
.has enzymes

Question 12

resolution

Answer 12

.ability to see more detail

Question 13

onion root cells

Answer 13

.dont contain chloroplasts
.contains mitochondria
.contain 80S ribosomes in cyto
.dont have pilli
.have cellulose cell walls

Question 14

role of the membrane in RER

Answer 14

.maintains different conditions from cell cytoplasm
.separating proteins synthesised from cell cytoplasm
.hold ribosomes/enzymes in place

Question 15

use for mito

Answer 15

to provide lots of ATP

Question 16

use of golgi

Answer 16

.modify and packages protein

example- modify protein for secretion of mucus in goblet cells

Question 17

features of cells

Answer 17

animal:
.divides via cytokinesis
.has nucleus
.no cell wall
.has ribosomes

plant:
divides via cytokinesis
.has nucleus
.cell wall made of cellulose
.has ribosomes

yeast:
.divides via budding
.has nucleus
.cell wall made of chitin
.has ribosomes

bacterium
.divides via binary fission
.no nucleus
.cell wall made of muerin
.has ribosomes

Question 18

structual features of mito that proves that it has evolved from bacteria

Answer 18

.size is similar to a bacterium
.contains circular DNA
.contain 70s ribosomes
.have plasmids
.have double membrane

Question 19

why early eukaryotes were able to grow more quickly than cells that did not possess
mitochondria.

Answer 19

.would be able to respire aerobically
.thus producing more ATP
.ATP needed for DNA replication
.more ATP = faster metabolic processes

Question 20

bacterium and fungus structures

Answer 20

B-
.free ribo in cytoplasm
.DNA in single loop
.cell wall present

F-
.free ribo in cytoplasm
.membrane bound nucleus
.cell wall present

Question 21

Describe how a molecule is prepared and secreted by cells of the salivary gland after translation
has taken place.

Answer 21

.transport vesicles from RER
.modification of protein at golgi apparatus
.then packaged into secretory vesicle
.vesicles move along the cytosleleton
.vesicles fuses with membrane
.exocytosis occurs

Question 22

translation of proteins

Answer 22

.mRNA transported out of nucleus
.mRNA transported to ribosome
.translation of protein occurs at ribosomes
.tRNA brings amino acids
.peptide bonds form between adjacent amino acid
.polypeptide processed through golgi

Question 23

how the genetic code in the genes codes for protein

Answer 23

.3 bases code for 1 amino acid
.sequence of bases determines sequence of amino acids

Question 24

cytoskeleton functions

Answer 24

.forms spindle fibres to move chromatids during mito and meio
.gives mechanical strength to cells
.maintains shape of the cell
.movement of molecules within the cell
.holds organelles in position

Question 25

how do vesicles and other things move inside the cell

Answer 25

.attach to cytoskeleton
.moved by protein motors

Question 26

function of epithelial cells in airways of mammals in the defence against pathogens

Answer 26

.goblet cells secrete mucus
.mucus traps pathogens
.cillia sweep mucus
.cytoskeleton moves the cillia