cell structure

Question 1

how do light microscopes work and what is the resolution and magnification?

Answer 1

light microscopes shine light through the specimen

low resolution of 0.2micrometres
low magnification of x1500

Question 2

how do transmission electron microscopes work and what is the resolution and magnification?

Answer 2

uses electromagnets to focus a beam of electrons which is transmitted through a specimen. denser parts absorb more electrons so appear darker

high resolution of 0.0002micrometres or 0.2nm

magnification of x1000000

Question 3

how do scanning electron microscopes work and what is the resolution and magnification?

Answer 3

they scan a beam of electrons across the specimen which knocks off electrons which are gathered in a cathode ray tube to form an image
the images are of the surface of the specimen and can be 3D

resolution of 0.002micrometres or 2nm

magnification of x500000

Question 4

what is a laser scanning confocal microscope?

Answer 4

uses laser beams to scan a specimen which is tagged with a flourescent dye

light is focused through a pinhole onto a detector which is hooked up to a computer and creates an image which can be 3D
can be used to look at objects at different depths

Question 5

what is the difference between magnification and resolution?

Answer 5

magnification is how much bigger thr image is than the specimen

resolution is how detailed the image is- how well the microscope distinguishes between two points that are very close together

Question 6

why do you stain a specimen in light microscopy?

Answer 6

to add contrast to be able to identify different cellular comoponents

Question 7

what does methylene blue stain?

Answer 7

DNA

Question 8

what does eosin stain?

Answer 8

cytoplasm

Question 9

what is the equation for magnification?

Answer 9

image size/object size

Question 10

what does the nucleus do?

Answer 10

controls cells activites and contains instructions to make proteins

Question 11

what does the nucleolus do?

Answer 11

makes ribosomes

Question 12

what does the nuclear envelope do?

Answer 12

cotains pores which allow substances to move between the nucleus and the cytoplasm

Question 13

what does the rough endoplasmic reticulum do?

Answer 13

folds and processes proteins made in its ribosomes

Question 14

what does the smooth endoplasmic reticulum do?

Answer 14

synthesises and processes lipids

Question 15

what does the golgi aparatus do?

Answer 15

processes and packages lipids and proteins - makes lysosomes

Question 16

what do ribosomes do?

Answer 16

synthesise proteins

Question 17

what do lysosomes do?

Answer 17

contain hydrolytic enzymes that are used to digest invading cells or digest worn out components of the cell

Question 18

what do mitochondria do?

Answer 18

they are the site of aerobic rspiration

Question 19

what does the plasma membrane do?

Answer 19

regulates movement of substances into and out of cell

Question 20

what do the chloroplasts do?

Answer 20

site of photosynthesis

Question 21

what does the cell wall do?

Answer 21

rigid structure of cellulose to support plant cells

Question 22

what do cilia do?

Answer 22

move substances across surface

Question 23

what do flagella do?

Answer 23

move cell around

Question 24

what do centrioles do?

Answer 24

involved in the separation of chromosomes during cell diviison

Question 25

what is the importance of the cytoskeleton?

Answer 25

give mechanical support to cells

aids transport within cells

enables the cell to move (cilia and flagella)

Question 26

what is the cytoskeleton?

Answer 26

network of protein threads called microtubules and microfilaments

Question 27

describe the function of organelles in the synthesis of proteins

Answer 27

proteins are made at the ribosomes

new proteins are folded and processed at the RER

these proteins are then transported to the golgi aparatus in vesiciles to undergo further processing and

golgi packages proteins into vesicles to be transported around the cell

Question 28

what are the similarities and differences between eukaryotic and prokaryotic cells in terms of
size
DNA
nucelus 
cell wall
organelles
flagella
ribosomes

Answer 28

prokaryotic cells are smaller than eukaryotic 2micrometres vs 10-100micrometres

circular DNA for prokaryotic and linear DNA for eukaryotic

no nucleus in prokaryotic and a nucleus in eukaryotic

cell wall of peptidoglycan in prokaryotic, no cell wall in eukaryotic

few organelles and no membrane bound in prokaryotic
lots of organelles in eukaryotic

flagella made of flagellin arranged in helixes in prokaryotic and flagella of microtubules in 9+2 formation in eukaryotic

70S ribosomes in prokaryotic and 80S ribosomes in eukaryotic