2.1.1 - cell structure🦠

Question 1

the nucleus

Answer 1

contains coded genetic info in the form of DNA molecules and directs synthesis of all proteins required by the cell

Question 2

lysosomes

Answer 2

specialised form of vesicles, contains hydrolytic enzymes
breaks done waste material and pathogens

Question 3

RER

Answer 3

ribosomes bound to the surface and is responsible for the synthesis and transport of proteins

Question 4

ribosomes

Answer 4

no membrane, constructed of RNA molecules made in the nucleolus of the cell
site of protein synthesis

Question 5

golgi apparatus

Answer 5

formed of cisternae and no ribosomes
modifies proteins and packages them into vesicles

Question 6

cellulose cell wall

Answer 6

surrounds the plant cell
substances can move in and out as it is freely permeable
gives plant cell its shape - rigid
defence mechanism

Question 7

vacuoles

Answer 7

plant cells have large permanent vacuoles, maintains rigid framework, selectively permeable tonoplast membrane

Question 8

chloroplasts

Answer 8

responsible for photosynthesis in plant cells

Question 9

structure of chloroplasts

Answer 9

double membrane structure, fluid inside (stroma), several thykaloids, grana contain the chlorophyll

Question 10

how does a light microscope work?

Answer 10

light passes through one or more lenses to produce an enlarged image of a specimen - there are two lenses (eyepiece and objective), allowing for a higher magnification

Question 11

nigrosin/ congo red?

Answer 11

negatively charged dyes and are repelled by negatively charged cytosol - these leave cells unstained, meaning they stand out against the stained background.

Question 12

differential staining

Answer 12

can distinguish between different types of bacteria

Question 13

gram stain technique

Answer 13

used to separate bacteria into two groups (positive and negative)
- positive will remain violet stain
- negative have thinner walls and will lose the stain

Question 14

acid fast technique

Answer 14

used to identify members of mycobacterium - after dying with carbolfushin dye and washed with dilute acid, the mycobacterium will retain the red stain

Question 15

resolution

Answer 15

ability to see individual objects as separate entities

Question 16

how do you calibrate a microscope?

Answer 16

1. stage micrometer in place and the eyepiece graticule in eyepiece
2. get scale on micrometer slide in clear focus
3. align the micrometer scale with the scale in the eyepiece

Question 17

how does a laser scanning confocal microscope work?

Answer 17

moves a single spot of focused light across a specimen, causing florescence from the components labelled with a dye - light of a longer wavelength and lower energy is emitted to produce a magnified image

Question 18

the cytoskeleton

Answer 18

present throughout the cytoplasm of all eukaryotic cells - it is a network of fibres

Question 19

microfilaments

Answer 19

fibres formed from the protein actin.
responsible for cell movement and cell contraction during cytokinesis

Question 20

how is DNA contained in the nucleus

Answer 20

with a double membrane called a nuclear envelope - this contains nuclear pores that allow molecules to move in and out of the nucleus

Question 21

nucleolus

Answer 21

area within nucleus, produces ribosomes

Question 22

mitochondria

Answer 22

site of the final stages of cellular respiration
double membrane - inner folds to form cristae
matrix in the interior
contains own small amount of dna

Question 23

vesicles

Answer 23

small membrane sacs that specialise in moving products into out of and within a cell

Question 24

centrioles

Answer 24

composed of microtubules
two form the centrosome (involved in the assembly of spindle fibres in cell division

Question 25

flagella

Answer 25

enables cells to move, in some they are used as a sensory organ

Question 26

clilia

Answer 26

stationary - role within sensory organs mobile - beat in a rhythmic manner, creating a current and cause objects to move

Question 27

SER

Answer 27

responsible for lipid and carb synthesis, and storage

Question 28

microscope

Answer 28

an instrument that makes small objects look larger

Question 29

pros of light microscopes

Answer 29

relatively cheap and easy to use, in colour

Question 30

cons of light microscopes

Answer 30

low resolution, meaning they cannot see smaller organelles

Question 31

squash slides

Answer 31

wet mount and then lens tissue used on cover slip - for soft samples

Question 32

staining

Answer 32

increasing the contrast as different components take up stains to different degrees, which allows the components to become visible and therefore can be identified

Question 33

crystal violet/methylene blue?

Answer 33

positively charged dyes which attract to negatively charged materials in the cytoplasm

Question 34

magnification

Answer 34

how many times larger the image is that the actual size of the object being viewed

Question 35

how can resolution be increased?

Answer 35

by using beams of electrons which have a wavelength thousands of times shorter than light

Question 36

formula for magnification

Answer 36

image size/actual size

Question 37

transmission electron microscopes

Answer 37

beam of electrons is transmitted through a specimen and focused to produce an image

Question 38

scanning electron microscope

Answer 38

beam of electrons is sent across a surface of specimen and the reflected electrons are collected - 3D images

Question 39

process of protein transport

Answer 39

1 - synthesised on the ribosome on RER 2 - pass into cisternae and packaged 3 - vesicles move it to golgi apparatus 4 - vesicles then take to the cell surface membrane so that the proteins can fuse with it

Question 40

purpose of cytoskeleton

Answer 40

shape and stability of the cell holds organelles in place controlls cell movement

Question 41

microtubles

Answer 41

globular tubulin proteins polymerise to form tubes that are used to form a scaffold like structure that determines the shape of a cell acts as tracks for movement of the organelles

Question 42

intermediate fibres

Answer 42

fibres that give mechanical strength to cells and maintain their integrity

Question 43

what feature of the cell would indicate that it is well adapted for producing hormones

Answer 43

lots of ribsomomes on the RER for protein synthesis