key concepts

Question 1

nucleus

Answer 1

surrounded by a nuclear envelope consisting of 2 mebranes which contains pores allowing molecules to enter and leave the nucleus . Contains DNAin form of chromatin and a nucleolus which is the site of ribosme production as it contains ribosomal DNA

Question 2

rER

Answer 2

series of connected flattened sacs enclosed by a membrane with ribosmes on the surface- folds and processes proteins- proteins made on rer are transferred through er to other parts of cell

Question 3

sER

Answer 3

interconnected tubes- produces and processes lipids and steroids, single membrane bound sacs

Question 4

Golgi apparatus

Answer 4

a series of fluid-filled, flaterend and curved sacs (cisternae)with vesicles surrounding the edges- packaging and modifying materials prossesd in the ER into vesicles ready for export, single membrane bound

Question 5

mitochondria

Answer 5

2 thin membranes make up the wall, the inner is folded forming finger like projections called cristae-project into the interior which contains an organic matrix-contains their own DNA, enzymes and ribosomes for respiration -where latter stages of aerobic respiration occurs-synthesis of ATP

Question 6

Lysosome

Answer 6

spherical sacs bound by a single mebrane containing digestive enzymesinvolved in the breakdown of unwanted structures in the cell, destruction of whole cell (autolysis), digest pathogens, digest old organelles

Question 7

ribosomes

Answer 7

made of RNA and protein, can be free in the cytoplasm or bound to ER- site of rpoetin synthesis

Question 8

centriole

Answer 8

hollow cylinder containing a ring of 9 protein microtubules arranged at righjt angle to each other-involved in cell division of the making of the spindle and ttransport within the cell cyroplasm

Question 9

Cell surface membrane

Answer 9

Phospholipid bilayer which controls exchange of materials between internal and external environments

Question 10

process products from ER take in golgi

Answer 10

1) in rer amino acids joined by peptide bonds forming polypeptide chains forming primary structure of protein- folded into 3-D shape / secondary or tertiary structure}
2) packaged into vesicles at the end of the rER and vesicles move the Golgi where it fuses
3)proteins modified- quaternary structure produced
4)modified protein leaves Golgi through secretory vesicles and fuses with cell membrane for exocytosis

Question 11

differences and similarties between eukaryortiv and prokaryotic cells

Answer 11

Eukaryotic
have membrane bound organelles: single (Vacuole, Lysosome, Golgi Apparatus, Endoplasmic Reticulum) and double (Nucleus, mitochondria and chloroplast)
80s ribosomes
some eukaryotic cells have cellulose cell walls
DNA is linear in eukaryotic cells and associated with histone proteins
prokaryotes
do not have a nucleus but instead have circular chromosomal DNA and plasmids found in cytoplasm
70s ribosomes
prokaryotes have a cell wall made of a peptidoglycan
have mesosomes- in folding, contains ezymes for repsiration
capsule-retains moisture, aids adhesion- a protective mucus layer which prevents dehydration
pilli-transfer genetic material- allow bacteria to attach to surfaces and involved in cell-to-cell attachment

Question 12

how is DNA organised in a prokaryotic cell

Answer 12

large circular DNA
DNA not associated with histone proteins
found as plasmids
located in the cytoplasm and not inside the nucleus

Question 13

what happens to lysoymes once their contents have been digested

Answer 13

fuse with the cell mebrane and contnets of lysosyme relased from the cell through excocytosis

Question 14

capsule

Answer 14

mointoring moisture in cell

Question 15

pilli

Answer 15

dna transfer and adhesion

Question 16

mesosomes

Answer 16

enzymes that aid repsiration- infldoings