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Flashcards in organelles Deck (24)
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1

what is an organelle

they are to a cell what organs are to a complex organism,they have a defined function

2

what does compartmentalisation mean

separating organelles using cell membrane

3

what is the purpose of compartmentalisation in a cell

to have the correct condition for each organelle e.g.pH levels

4

how does an electron microscope work

uses a beam of electrons to create an image of the specimen

5

advantages of electron microscopes

greater resolving power and higher magnification

6

disadvantages of electron microscopes

needs a specially designed room and training to operate them - expensive -

7

describe the structure and function of the nucleus

bounded by two membranes which together make the nuclear envelopehas pores to allow mRNA to pass throughgranular material in the nucleus is nucleoplasm. it contains chromatin made of coils of DNAthe nucleolus is within the nucleus

8

describe the structure and function of the nucleolus

spherical bodysites of formation of rRNA a constituent of ribosomesdarker heterochromatin - made from densely packed DNAlighter euchromatin - less dense, DNA acts as a template for RNA synthesis

9

describe the structure and function of rough endoplasmic reticulum

is an elaborate system of parallel double membrane forming interconnected flattened sacs called cisternaehas ribosomes on the outer surface which is what gives it a rough look. present in large amounts in cells that make proteinsribosomes transport the proteins made

10

describe the structure and function of the ribosomes

made up of two subunits - a small and a large onethey are the 'protein builders' of the cellfound floating in the cytoplasm or attached to rERinvolved in protein synthesis

11

describe the structure and function of the golgi body

stack of flattened double membrane sacs called cisternaesurrounded by spherical membranes called vesicles involved ni the modification of proteinspackage proteins into vesiclesbuilds lysosomes

12

describe the structure and function of lysosome

spherical vesicle containing enzymes made by the golgi body pinching off a small specific vesicleinvolved in digesting material that enters the cell

13

describe the function and structure of the centriole

help the cell in mitosis and meiosis groups of threads attached called mitotic spindle made of microtubules go to poles of nucleus when cell is dividing

14

describe the structure and functions of cilia and flagella

cilia --- 9 pairs of microtubules around edge and 2 in centrehair like organelles that line surfaces of cells and beat in rhythmic wavesflagella --- 'organ' of movement need liquid environment to move

15

describe the structure and function of cell membrane

proteins and phospholipids make up the membranemembrane is made up of 3 'bands' which can be seen as a lighter band sandwiched between two dark onescontrol movement in and out

16

describe the structure and function of mitochondrion

has an inner and outer membrane inner membrane layers fold over to form cristae and improve surface area matrix pattern of inner membrane containing ribosomes and circular DNAcellular respiration - keep the cell full of energy muscle cells have lots of mitochondria

17

describe the structure and function of chloroplasts

outer and inner membrane containing starch/sugars, stroma and thykaloid stacks or granaproduce food for the cell chlorophyll is on the surface of each thykaloid stack to capture light thykaloid stacks are held together by storm lamellae which keep the stacks a safe distance away and increases efficiencystroma - where carbon is fixed and sugars are synthesisedchlorophyll - common structure called porphyrin ring

18

what does magnification mean

the degree to which the size of an image is larger than the image itself

19

what does resolution mean

the degree to which it is possible to distinguish between two objects that are very close together

20

how can you work out the actual size of a specimen

magnified size/ magnification x actual size

21

how can you convert between a)cm to mm b) mm to micrometres c) micrometres to nanometres

a) x10b) x 1000c) x 1000

22

describe the process of protein trafficking

protein synthesised of ribosome of ERprotein enters the cisternae of the RERprotein is folded into a 3d shapevesicles containing protein pinch of the ERvesicles travel to golgi body vesicles fuse with golgi bodyprotein is modified vesicles pinch off golgi body vesicles move to cell membrane and fusecontents of vesicle is released

23

what is exocytosis

vesicles move to cell membrane and use with it to become part of the membrane, contents leave vesicle

24

what is an organelle

they are to a cell what organs are to a complex organism,they have a defined function