Chapter 2

Question 1

Cytoskeleton function

Answer 1

• forms fibres necessary for shape and stability of cells
• organelles are held in place by the cytoskeleton and it controls movement of organelle

Three componetd
= - microfilaments
- contractile fibres from actin protein
- responsible for cell movement and cell contraction during cytokinesis

Microtubules
Intermediate fibres

Question 2

Microtubules

Answer 2

• Globular tublin proteins polymerise to fork tubes thst are used to form a scaffold like structure thst DETERMINES SHAPE OF CELL
• also act AS TRACTS FOR MOVEMENT of organelles like vesicles

Spindle fibres are made from theee

Question 3

Intermediate fibres

Answer 3

Give mechanical strength to cell and help maintain integrity

Question 4

Cytoskeleton summary

Answer 4

Intermediary fibres
- contractile proteins made from actin allow whole cell MOVEMENT, also help contraction twke place in mitosis
Microtubules
- these globular Tubulidentata proteins that POLYMERISE to form scaffold like structured thst determine the shape of the cell
- also act as tracks for movement if organelles around the cell, including vesicles (like lysosomes which are just vesicles with hydrolytic ensymes with three functions, apoptosis, phagocytosis help, and also digesting old material)

Intermediate fibres- give mechanical strength snd integrity ti cell

Question 5

What are centrioles , centrosome, what made from ?

Answer 5

They are part of cytoskeleton made from MICROTUBULES
Two combined is the CENTROSOME
This is duplicated in mitosis and helps form SPINDLE FIBRE for the process and organisation, in where microtubules attack from the centrosome to the chromosome plste

Question 6

Centrioles found everywhere?

What other function dintheybhave ?

Answer 6

Not in most fungi snd plants

If orgsnism has flagella or Cillia , it is thought to help position these “

Question 7

Flagella

Answer 7

Flagella enable movement = motility p
- in some cells used as a sensory organelle detecting chemical changes in cells environment

These are whipmlike

Question 8

Cillia + two typed ?

Answer 8

Can be stationary or bobble

Stationary
- present on surface of many cells and have an importsnt function in sensory organs such as the NOSE

Question 9

Mobile Cillia

Answer 9

This one is the one that caused MOVEMENT

• they best in rhythmic fsdhiojneuoduncresred s current snd causes objected adjacent to cell to love, for example in cilalted tissue which causes mucus to move down to digestive system in trachea

Question 10

Structure if cilla and flagella

What drtcutuee does this

Answer 10

9+ 2 arrangements

This was two central mictruhuoed which are black surrounded by 9 pairs of mictroibuled like a wheel

Again 9mpaird of microtubules in a ring surrounding two microtubules in the middle

Question 11

What organelles involved in proteins yt he Neids ?

Answer 11

This happens in the ribosomes and starts in nucleus / as dna is trsncfibedto RNA and escape via nuclesrporem

Involves ribosomes firsts, endoplasmic reticulum more, Golgi apparatus etc

Question 12

Endoplasmic reticulum, whst is ti snd what is difference between rough and smooth

Answer 12

Thenisna network of membranes enclosed in flattened sacs called cisternae

Connected to outer nucleus l-YDRSTE PRODUCTION AND STORSGEN
- rough cintaijdnRIBSOKED (so kinda rough) m responsible for sythesis and transport of proteins

Thstsit, smooth lipid and carbohydrate , rough proteins and trandorotif em
-smooth is the SITE FOR LIPID SND CSRBOH

Question 13

What do secretory cells have more than as a result

Answer 13

Need to release more ensymes or hirmones, so need more ROUGH ER so. Ore proteins cna be produced and transported

Question 14

Ribosomes?

Answer 14

Site of protein synthesis , either floating or attached to reticulum to make rough p

• they DONT HAVE MEMBRANE
• made from RNA molecules made in NUCLEOLUS (which is site, does this by combine rRNA with proteins to make ribsokedm, and RNA produces rRNA)

Mitochondria sjdnchlorolsdtshave own ribosomes and dna , and double membrwne = endisymbitouc

Question 15

Golgi apparatus?
How structure similar
- what type of vesicles does it mske
What is cis and trans face and where

Answer 15

Simialr to smooth ER AS IT HAS mambrsnius sscs in closed cslled cisternse , does nit have ribosomes

• function of modifying oroteind by giving carbon chains, snd PACKAGAING THRM INTO VESICSKED SO THEY CSN BE TRSNSORTED
• these could be secretory vesicles, to leave the cell by exocytosis
  -or vesicles to be kept in the cell as lysomes which special
  They enter from cis FACE, and exit from trans face

Theee make them secretory vesicles, whereas rer makes them. Transport vesicles to the cis fsce

Question 16

IMPORTANT THING ABOUT RIBOSOMES?

Answer 16

Not membrwne bound!

Question 17

Question about describe the process of proteins synthesis?

Answer 17

1) first transcription happens of DNA to mRNA which leaves through nuclear pores
2) now it goes to the ribosomes in ROUGH ER and translation of proteins occur here.
3) now passed through cisternae here and PACKAGED INTO TRANSPORT VESICLES
4) using cytoskeleton it makes way to the cis face of Golgi apparatus
5) here they are modified if needed by adding chains etc and REPACKAGED but into secretory vesicles, and these could leave via trans face and cytoskeleton by exocytosis

This happens as vesicles both have phospholipids , so fude can happens and product is Denton

But if they aren’t leaving these won’t be secretory vesicles, rather stay sd lysosomes inside.

Question 18

Cell wall

Answer 18

Acts as a barrier to pathogens
Content of wall increase tiger oressure , making it RIGID and giving support to cell

Fällt permeable

Question 19

Vacuoles only plants have waffle

Answer 19

Membrwne if vacoule = tonoplast

• selectively permeable
• has sap
• plants have permanent vacuoles importsnt for tiger preddure ss water diffus ehere doesn’t affect water protnisl

Question 20

Chloroplasts

Structure first

Answer 20

Responsible for photosyhtendie
-double membrwne structure again like mitochonridrwn
- fluid enclosed here is STROMA
- internal network membranes which form flattened sacs are called THYLAKOIDS
- serval thylakoids make a GRANUM
Grana are joined by membranes called LAMELLAE
The grana contain the chlorophyll pigments , which is where the light dependent part of ohtoosytnehdid takes placed

Question 21

Go over structure chlroplsdt again

Answer 21

Double membrwne
Internal fluid network = stroma
Internal network of membranes = thylakoids
Thylakoids multiple stack and form a Granum
Grans multiple connected by lamellae membranes

Grana contain CHLROPHYLL where light dependent revstiknd twke place

Inetnerlw membrwnes provide the large surface area needed for enzymes, pigment molecules and proteins needed for ohotydtheidd, just like how all the endures for repisrwiton found on internal network of membrwne for mit hoch drin too, the Cristae? (Matrix)

Question 22

What else about mitochondria

Answer 22

Starch produced is found as Strachey graind

MitcohndiraSLO has own circular DNA and ribosomes, do it can make own proteins and reproduce further efidence

Question 23

Old prokaytoed, Archae

Answer 23

Edtremiphuoee kifef I. Jndwne cinditiond like hydrothermal vented, salt lakes etc snd still do tofsy

But now common bacteria found on like soil etf

Question 24

Prowhrotyic fetwured

Answer 24

No membrwne bound organelles
No nucleus, dna is curcuslr loop of chomeodne d
Unicellular and simple , small

Question 25

DNA in prokaryote Second point ! Fundamental sd this different to us where Gegend switched in ir off oermeantlyn

Answer 25

Only have one molecule of DNA A chronometer , so circular dna and this is supercooled - genes are also grouped into operons, meaning s number can be turned on and off at the same time,

Question 26

Ribosomes of prokaryotic

Answer 26

Smaller , 70s compared to 80s, and 80s more cmo,pelt Here mitochondria and chloroplasts both have 70s?

Question 27

Cell wall

Answer 27

Here is made from peptidoglycan rather than cellulose in plants and chitin in like fungi or dokethintn

Question 28

How is prokaryotic flagella different ?

Answer 28

Does NOT HAVE 9+2 microtubules arrangements , thinner - energy needed to rotate filaments is not from ATP like eurjsottif bu rather from CHEMIOSMOSIS FLAGELLA is attached to the cell by a BASAL body and rotsted by a moelcuslr motor effect Basal body like an anchor and then molecular motor causes whipmlike movement causing git to move foresrf

Question 29

So specific organelle?

Answer 29

Different cell walls Vacuoles chldopskdts Plasmids slime capsule pili etc DNA is arrnsged as multiple chromosomes from chromatic from histones snd dna which is very effeicnet fornowdkwgijtn , genes swirduedoff and on indicusllt in eukaryotic but can happen sake tike on prokaryotic But prokaryotic genes are operojs

Question 30

What is the endosymbiosis theory

Answer 30

Idea that iposdys and potentially other organisms were originally free badgering, but I get der by a. Ore complex orhsnikd snd then lived within that body’s irgsnikd since then leading to evolution of complex bodied

Question 31

What is Vedic me ?

Answer 31

- from study if mitochondria and chlroplsdt - they both have circular dna , with 70s ribsomed just like bacteria - divide by binary fission toom - also have DOUBLE, ME,BRWNE TOO and can reproduce like bacteria too

Question 32

Finally what membrwnes

Answer 32

Nucleus double membrwne with nuclear enve,one, and mitochdinria chlroplsdt but not ribosome