Mitochondria, Plastids, Extracellular Matrix, Cytoskeleton

Question 1

What is the inner membrane of the mitochondria called?

Answer 1

Cristae

Question 2

Which of the mitochondria’s two membranes is larger?

Answer 2

The inner membrane

Question 3

What are the pores and transporters of the mitochondria like in comparison to the nuclear pores?

Answer 3

The nuclear pores go through both membranes, whereas the mitochondria’s pores only go across one membrane at a time. There are seperate outer and inner mitochondrial membrane transporters.

Question 4

How many mitochondria may a eukaryotic cell have?

Answer 4

Between one and thousands

Question 5

What is meant by the mitochondria is dynamic?

Answer 5

They can change shape, fuse and divide. They form a branched tubular network

Question 6

What organisms are plastids found in?

Answer 6

Just plants and algae, and few protists

Question 7

Where are amyloplasts commonly found?

Answer 7

In starchy roots

Question 8

What is a function of chromaplast’s colour?

Answer 8

To communicate, for animals and insects - pollinators

Question 9

What is plastid interconversion?

Answer 9

Plastids are not fixed in their function, they can interconvert between different plastids/functions

Question 10

How many membranes do chloroplasts have?What are their names?

Answer 10

Three, the outer membrane, the inner membrane and the thylakoid membrane

Question 11

What is the name of the liquid space between the inner membrane and the thylakoid membrane of a chloroplast?

Answer 11

The stroma

Question 12

According to endosymbiotic theory, how did the nucleus and the ER evolve? What evidence supports this?

Answer 12

The plasma membrane infolded on itself around the DNA to form the nucleus, and the ER came from the extra infolded membrane around the nucleus. The nucleus having a double membrane supports this theory

Question 13

According to endosymbiotic theory, how did the mitochondria and chloroplasts evolve?

Answer 13

The mitochondria and chloroplast is thought to have originally been a prokaryote that was taken up by phagocytosis by a eukaryote, and it then formed a symbiotic relationship and remained in the cell to carry out their functions.

Question 14

What 5 pieces of evidence support the endosymbiotic theory of how the mitochondria and chloroplasts evolved?

Answer 14

(1) Both the mitochondria have a double membrane, (2) they both have circular chromosomes (like prokaryotes), (3) their biochemistry resembles bacterial biochemistry, (4) they divide like bacteria and cannot be synthesised, (5) and their ribosomes are more similar to bacterial than eukaryotic.

Question 15

What bacteria are chloroplasts thought to have come from?

Answer 15

Filamentous cyanobacteria

Question 16

What bacteria are mitochondria thought to have come from?

Answer 16

A pathogenic bacteria - Rickettsia

Question 17

By which method do mitochondrial proteins that are made in the nucleus move into the mitochondria?

Answer 17

Post-translational translocation

Question 18

Is mitochondrial DNA inherited from the paternal or maternal line?

Answer 18

Maternal

Question 19

What is a haplogroup?

Answer 19

A genetic population who share a common ancestry through a single parent

Question 20

What types of organisms have a cell wall?

Answer 20

Plants, fungi, bacteria, archaea and some protists

Question 21

What are the long rigid fibres in the ECM of animals made of?

Answer 21

Glycoproteins, such as collagen and elastin

Question 22

What is the embedding material in the ECM of animals made of?

Answer 22

Proteoglycans

Question 23

Describe the structure of collagen fibres

Answer 23

Three amino acid chains twisted in a unique triple helix, which are then grouped into collagen fibrils which are again bundled to be the collagen fibres

Question 24

Collagen contains two unusual modified amino acids, what are these?

Answer 24

Hydroxyproline and hydroxylysine

Question 25

What is the main carbohydrate in proteoglycans?

Answer 25

Glycosaminoglycans (GAGs)

Question 26

What part of the ECM provides elasticity for animals?

Answer 26

Proteoglycans along with elastin

Question 27

How are proteoglycans made?

Answer 27

They start by being synthesised in the ER, and the carbohydrate molecules are then attached in the ER or golgi, to then be secreted by exocytosis

Question 28

What are the long rigid fibres in the cell wall/ECM of plants made of?

Answer 28

Cellulose

Question 29

What is the embedding material of the cell wall/ECM in plants commonly made of?

Answer 29

Pectin, hemicellulose and proteins

Question 30

Why is the ECM of plants more rigid and stationary than that of animals?

Answer 30

Because of their non-motile lifestyle, they need more strength and protection over elasticity

Question 31

What would happen to the regular shape of plant cells if the cell wall was removed?

Answer 31

They would become round cells and would not stay together as well

Question 32

Where is cellulose synthesised?

Answer 32

Directly at the plasma membrane by cellulose synthase

Question 33

What are the cell walls of some protists made of?

Answer 33

Silica

Question 34

True or false: All Eukaryotes have a cytoskeleton

Answer 34

True

Question 35

What two proteins make the heterodimers of microtubules?

Answer 35

alpha-tubulin and beta-tubulin

Question 36

What is the centrosome?

Answer 36

The main organising centre of many cells

Question 37

Which end of the microtubules grow outwards from the organising centre?

Answer 37

The plus end

Question 38

Which way does Dynein move along microtubules?

Answer 38

From the plus end to the minus end

Question 39

Which way does Kinesin move along micotubules?

Answer 39

From the minus end to the plus end

Question 40

What is the mitotic spindle?

Answer 40

An array of microtubules with associated proteins which functions to seperate chromosomes during mitosis

Question 41

Describe the structure of Actin microfilaments

Answer 41

Actin forms a solid rod composed of a twisted double chain, these have directionality with a plus and minus end

Question 42

What is the motor protein of Actin filaments?

Answer 42

Myosin

Question 43

Which direction does Myosin move in along the Actin microfilaments?

Answer 43

Towards the plus end

Question 44

Describe where Actin microfilaments are found in the cell

Answer 44

In bundles around the edge of the cell by the plasma membrane

Question 45

What is the prokaryotic flagella composed of?

Answer 45

The filament (composed of the protein flagellin), the hook and the basal apparatus which acts as a motor