Lecture 3-4 Cytoskeletons of Eukaryotic Cells

Question 1

11. Cell cytoskeleton maintains structure and reinforces plasma membrane

Answer 1

11. Cell cytoskeleton maintains structure and reinforces plasma membrane

Question 2

What is the equivalent structure in Mitochondria to the Chloroplast’s Stroma? a) Inner Mitochondrial Membrane b) Intermembrane compartment c) Cristae Folds d) Matrix e) Outer Mitochondrial Membrane

Answer 2

Answer 1: Matrix

Question 3

Cells in the lining of the stomach create a digestive enzyme (Pepsin) that is excreted into the lumen of the stomach cavity through exocytosis. Which organelle would you expect to find in disproportionately high abundance in these cells relative to other cell types? A. Golgi Bodies B. Mitochondria C. Rough ER D. Smooth ER E. Chloroplasts
Answer 2: ER

Answer 3

h

Question 4

In Plasma membrane what changes proteins?

Carbohydrate groups attached to the integral proteins

Answer 4

h

Question 5

1. Cytoskeletons

a. Most important in animal cells

Answer 5

1. Cytoskeletons

a. Most important in animal cells

Question 6

microtubules

Answer 6

b. Made up of
i. Microtubules
1. Made of tubulin (alpha + and beta -)
2. 25 nm in diameter

3. Tubulin molecules can disassemble and reassemble
4. Hollow to save materials
5. Animal cells move, malleable structure of tubulins allows for quick dynamic change
6. Comprised of assembling tubulin subunits
7. Anchored on Microtubule Organising Centers
8. resist compression
9. main component of centrioles – microtubules originate from (2 microtubules together)
10. Provides tract for vesicle (travel on outside)
11. Important in cell division

Question 7

intermediate filaments

Answer 7

ii. Intermediate filaments
1. Fibrous proteins (supercoiled into thicker cables)
2. Function in tension bearing
3. Don’t have + or – ends like microtubules/microfilaments
4. Only found in multicellular organism

Question 8

microfilaments

Answer 8

iii. Microfilaments
1. 5-7 nm
2. Helical double strand polypeptide
3. More flexible than microtubules (there to secure things in place)

Question 9

Movement and Cytoskeleton
Cytoskeleton provides not only support, but also
potential for cellular transport
Motor Proteins – e.g. kinesins and dyneins –
attach and move relative to components of
cytoskeleton

Answer 9

c. Provides support and potential for cellular transport
i. Eukaryotic Flagellum: Motor proteins (kinesins) and dyneins attach and move relative components of cytoskeleton
1. How kinesins walk (spends ATP, protein changes shape, moves forward due to attraction)
2. How Dynein walks (Spend ATP, protein release, opposite direction of charge arm ratchets up along railroad)
3. Movement of cilia and flagella (examples of Dynein movement) (tries to ratchet cannot so it bends, whip like movement) Ex: movement of sperm
4. Dynein arm connected to microtubules vs funky walking of Kinesin

Question 10

see diagram for movments and cilia vs flagellum movements

Answer 10

words

Question 11

Question Which of the following structures would allow communication between the cells of the heart muscle tissue, resulting in the coordinated beating of the heart?
a) gap junctions b) tight junctions c) anchoring junctions d) desmosomes e) plasmodesmata

Answer 11

hh

Question 12

junctions see word

Answer 12

word

Question 13

PLant cells have cell wall

Answer 13

see diagram