CMB1004/L01 Eukaryotic Cells

Question 1

Name the 3 domains of life.

Answer 1

Bacteria
Archaea
Eukaryota

Question 2

What can all life forms on Earth be traced back to?

Answer 2

LUCA (Last Universal Common Ancestor)

Question 3

What theory encompasses the fundamental characteristic of cells being derived from other cells?

Answer 3

Darwin’s theory of descent with modification

Question 4

Describe how modern eukaryotes evolved from ancient eukaryotic cells.

Answer 4

Bacterial endosymbiont evolved into modern mitochondria

Question 5

What is the most widely used phylogenic marker?

Answer 5

Small subunit ribosomal RNA (SSU rRNA)

Question 6

How can a phylogenic tree be inferred?

Answer 6

Nucleotide or amino acid sequence data

Question 7

What does branch length relate to in the SSU rRNA tree of life?

Answer 7

Genetic differences between species

Question 8

What governs protein transport and localisation in cells?

Answer 8

Intrinsic protein signals

Question 9

What is the Archibald theory of nucleus origin?

Answer 9

An endosymbiont or host-derived membrane could surround mitochondria within eukaryotic cells

Question 10

What is the Blobel theory of nucleus origin?

Answer 10

The membrane is host-derived so no new membrane material entered the cell

Question 11

Describe the Archezoa Hypothesis (phase 1).

Answer 11

Invagination of membrane of an ancient procaryotic cell formed the nucleus and ER

Question 12

What does the Archezoa Hypothesis suggest about ancient procaryotic cells?

Answer 12

There was a prokaryotic cell without mitochondria

Question 13

Describe the Archezoa Hypothesis (phase 2).

Answer 13

Bacterium was engulfed by an ancestral eucaryotic cell and became a mitochondrion

Question 14

What does the Archezoa Hypothesis suggest about ancestral eucaryotic cells?

Answer 14

They were anaerobes

Question 15

What is the name given to double-membrane bounded organelles in Archezoa?

Answer 15

Hydrogengenosomes and mitosomes

Question 16

What evidence supports the Archezoa Hypothesis?

Answer 16

Mitochondria and chloroplasts have their own DNA & ribosomes

Question 17

How do Paramecium bursaria and Chorella algae achieve symbiosis?

Answer 17

Paramecium contains heat for algal survival
Algae receives protection and gives the ciliate nutrition

Question 18

Which two organelles have endogenous origins?

Answer 18

Nucleus and RER

Question 19

Which two organelles have exogenous origins?

Answer 19

Mitochondria and plastids

Question 20

What organism was engulfed to become mitochondria?

Answer 20

Alpha-cyanobacteria

Question 21

What organism was engulfed to become chloroplasts?

Answer 21

Cyanobacteria

Question 22

Give 2 functions of the plasma membrane.

Answer 22

Receiving information
Import/export of molecules
Movement and expansion

Question 23

Which type of organism has no plasma membrane?

Answer 23

Xenobacteria

Question 24

Give the function of the cytosol.

Answer 24

Metabolic pathways
Protein synthesis

Question 25

Give the function of the nucleus.

Answer 25

Contains main genome
DNA and RNA synthesis

Question 26

Give the function of the endoplasmic reticulum.

Answer 26

Synthesis of most lipids
Synthesis of proteins for distribution

Question 27

Give the function of the Golgi apparatus.

Answer 27

Modification, sorting and packaging of proteins and lipids

Question 28

Give the function of lysosomes.

Answer 28

Intracellular degradation

Question 29

Give the function of endosomes.

Answer 29

Sorting of endocytosed (internalised) material

Question 30

Give the function of peroxisomes.

Answer 30

Oxidation of toxic molecules

Question 31

Give the function of mitochondria.

Answer 31

Oxidative phosphorylation
FeS cluster biosynthesis

Question 32

Give the function of chloroplasts.

Answer 32

Photosynthesis