cell structure

Question 1

what is the function of the nucleus

Answer 1

where DNA is stored, replicated and copied into messenger RNA (mRNA) (through transcription

Question 2

function of the nucleolus

Answer 2

part of the nucleus that produces ribosomes

Question 3

function of the nuclear envelope

Answer 3

double membrane that separates the contents of the nucleus from the cytoplasm

Question 4

function of the nuclear pores

Answer 4

gaps in nuclear envelope that allow substances to move in and out

Question 5

function of the cell membrane

Answer 5

a phospholipid bilayer that surrounds the cell, enables it to communicate and detect and respond to changes in the environment. it also acts as a physical barrier controlling what can enter and exit the cell

Question 6

function of extracellular matrix 


Answer 6

the material in between cells that holds tissues together

Question 7

function of cytoplasm

Answer 7

everything in the cell outside the nucleus; an aqueous fluid (cytosol). the site of many chemical reactions

Question 8

function of mitochondria

Answer 8

organelles that supply chemical energy to the cell. they are surrounded by a double membrane

Question 9

golgi apparatus

Answer 9

a complex membrane system which modifies, packages and directs proteins to where theyre needed

Question 10

function of the centriole

Answer 10

a pair of organelles that organises microtubules into spindles for cell division

Question 11

function of the vacuole

Answer 11

internal bags, surrounded by a membrane, cells use for storing food or waste

Question 12

function of lysosome

Answer 12

membrane bound organelles that contains hydrolytic (digestive) enzymes

Question 13

function of ribosomes

Answer 13

assembles amino acids to form proteins that are essential to carry out cellular functions

Question 14

function of smooth and rough endoplasmic reticulum

Answer 14

an extensive network of membranes that is studded with ribosomes (rough and is a site where proteins are made. the roles of the smooth endoplasmic reticulum include lipid and steroid synthesis and drug detoxification

Question 15

function of microfilaments

Answer 15

protein fibers that provide structure and support to eukaryotic cells

Question 16

function of microtubules

Answer 16

made from repeating tubulin subunits, help maintain the cell’s internal structure and move organelles around

Question 17

cell wall

Answer 17

rigid structure that surrounds plant cells to support and keep them rigid and strong, made of cellulose

Question 18

chloroplasts

Answer 18

site of photosynthesis, some parts happen in the grana and others happen in the stroma

Question 19

cillia

Answer 19

microtubules allow cillia to move, movement is used by the cell to move substances along the cell surface

Question 20

flagellum

Answer 20

microtubules contract to make flagella move, propell cells forward

Question 21

magnification formula

Answer 21

magnification= image size/actual size

Question 22

magnification definition

Answer 22

how much bigger the image is than the specimen

Question 23

resolution definition

Answer 23

how detailed the image is/ the ability to distinguish between two points that are close together

Question 24

light microscope advantages/disadvantages

Answer 24

advantages- inexpensive, portable, requires simple sample preperation,specimens can be dead or living
disadvantages-low magnification and resolution compared to electron microscope

Question 25

how can you prepare and examine a light microscope slide

Answer 25

wet mount or dry mount preperation examine- place the slide on the microscope stage and clip it in place. start with the lowest magnification lens and use the coarse adjustment knob to focus on the specimen

Question 26

transmission electron microscope advantages/disadvantages

Answer 26

advantages- high resolution, high magnification disadvantages- expensive, needs to be installed, complex sample preperation, risk of artefacts, black and white 2D images, specimens must be dead

Question 27

magnification and maximum resolution for TEM, SEM and light microscope

Answer 27

light- x1500, 0.2μm sem- usually less than 500,000, 0.002μm tem- could be more than x1,000,000 , 0.0002μm

Question 28

scanning electron microscope advantages and disadvantages

Answer 28

advantages- high resolution, high magnification, images produced are 3D disadvantages- expensive, needs to be installed, complex sample preperation, risk of artefacts, black and white images, specimens must be dead

Question 29

what is an artefact?

Answer 29

Visible structure caused by processing the specimen and not an actual feature of the specimen

Question 30

dry mount preperation

Answer 30

The solid specimen is placed either whole or sectioned by slicing with a large knife on the slide. A coverslip is placed over the top

Question 31

wet mount preperation

Answer 31

Specimen is submerged in liquid - such as water or immersion oil. Coverslip is placed on top at an angle to prevent air bubbles from forming underneath the coverslip

Question 32

use of an eyepeice graticule

Answer 32

to measure the size of cells and tissues when viewed under a microscope. to use an eyepiece graticule, you must calibrate it with a stage micrometer

Question 33

use of a stage micrometer

Answer 33

to calibrate the eyepiece graticule and measure the size of microscopic specimens

Question 34

use of staining in light microscopy

Answer 34

to observe and investigate different types of cells and cell structure in eukaryotic organisms

Question 35

methylene blue stain

Answer 35

stains DNA blue, defined nucleus

Question 36

iodine stain

Answer 36

stains starch, cell walls and nucleus yellow colour

Question 37

wright giemsa stain

Answer 37

differentiate between blood cells

Question 38

H & E stain

Answer 38

haemotoxylin - RNA and DNA blue/purple, eosin red- cytoplasm pink

Question 39

describe protein production

Answer 39

-proteins are produced on the ribosomes -proteins produced on RER make proteins that are extracted or attached to the cell membrane -free floating ribosomes in cytoplasm make proteins that stay in cytoplasm -new proteins produced on RER are folded and processed in RER then transported to the golgi apparatus in vesicles -at golgi apparatus proteins may undergo further processing, they enter vesicles to be transported around the cell -some proteins leave cell through exocytosis

Question 40

describe the cytoskeleton and its functions

Answer 40

-cytoplasm has a network of protein threads running through it, this is cytoskeleton -in eukaryotic cells, the proteins are arranged as microfilaments and microtubules -cytoskeleton is constantly changing, allows it to respond to intercellular changes and carry out its function -the four main functions are: -microtubules and filaments support the cells organelles by keeping them in position -also help strengthen the cell and maintain its shape -responsible for transport of organelles and material within the cell -proteins of cytoskeleton also help the cell to move