Lecture 5

Question 1

Endosymbiotic Hypothesis

Answer 1

Origin of mitochondria and chloroplast, arose from a primitive bacteria living inside a primitive eukaryote

Question 2

Endomembrane System

Answer 2

Membrane bound organelles that arose from infolding of membrane and are connected via vesicles

Question 3

Nucleus

Answer 3

Not technically part of endomembrane system, stores DNA as multiple linear chromosomes

Question 4

Inner Nuclear Membrane

Answer 4

Inner membrane of the nucleus

Question 5

Outer Nuclear Membrane

Answer 5

Outer membrane of the nucleus, continuous with the endoplasmic reticulum

Question 6

Nuclear Pore Complex

Answer 6

Transmembrane protein that spans both inner and outer nuclear membrane, provides a non-selective pore for most small molecules

Question 7

Nucleolus

Answer 7

Site of rRNA transcription and ribosomal unit assembly

Question 8

Ribosomal Subunit

Answer 8

Associated with unique rRNA’s, packaged with rRNA at nucleolus

Question 9

Nuclear Envelope

Answer 9

Created to protect nucleus from Oxygen, consists of both nuclear membranes

Question 10

Chromatin

Answer 10

A complex of DNA and proteins that forms a chromosome, organizes and protects DNA

Question 11

Nucleosome

Answer 11

A section of DNA wrapped around a histone octomer, attached by positive-negative interactions

Question 12

Histone Octomer

Answer 12

Composed of several positively charged proteins, 2 of each H2A, H2B, H3 and H4

Question 13

Solenoid/30 nm fibre

Answer 13

Nucleosomes stack with help of histones (H1)

Question 14

Looped Domains

Answer 14

30 nm fibre loops off non-histone scaffolding proteins

Question 15

Mitotic Chromosome

Answer 15

DNA in its fully condensed form

Question 16

Ribosomes

Answer 16

Enzymes of translation (catalyze peptide bonds)

Question 17

Rough Endoplasmic Reticulum

Answer 17

Where proteins destined for within the endomembrane system or secretion are translated on bound ribosomes, also responsible for protein quality control (chaperones are found here)

Question 18

Bound Ribosomes

Answer 18

Ribosomes bound to the rough endoplasmic reticulum, responsible for translating proteins destined for secretion or use within the endomembrane system

Question 19

Smooth Endoplasmic Reticulum

Answer 19

Responsible for ion storage (Ca2+), phospholipid synthesis, steroid synthesis, detoxification of drugs and alcohol

Question 20

Cis Golgi

Answer 20

Receives cargo from endoplasmic reticulum in vesicles

Question 21

Medial Golgi

Answer 21

Sorts and modifies cargo

Question 22

Trans Golgi

Answer 22

Sorts cargo into various destinations within endomembrane system, mostly the lysosome or plasma membrane

Question 23

Golgi Apparatus

Answer 23

Processes/packages lipid and protein molecules, made up of approximately 20 cisternae

Question 24

Vesicle Trafficking

Answer 24

Within golgi, cargo is transported between cisternae in vesicles

Question 25

Cisternae

Answer 25

Flattened, membrane bound sacs

Question 26

Cisternal Maturation

Answer 26

Within golgi, cargo is transported as cisternae mature, i.e. new vesicles form a new cis golgi, the old cis golgi becomes a new medial golgi, the old medial golgi becomes a new trans golgi, and the old trans golgi vesiculates

Question 27

Lysosome

Answer 27

Organelle responsible for digestion of molecules received from endocytosis

Question 28

Hydrolytic Enzymes

Answer 28

Enzymes found within lysosome and that function only at a pH of 5

Question 29

Autophagy

Answer 29

Self-eating, can be a response to extensive cell damage

Question 30

Cytoskeleton

Answer 30

Network of fibres extending through cytoplasm, responsible for cell support, motility and shape

Question 31

Microtubules

Answer 31

Responsible for compression resistance and movement within the cell, composed of tubulin dimers which form protofilaments and are then bundled into microtubules

Question 32

Motor Proteins

Answer 32

Change shape with ATP hydrolysis and generate force

Question 33

Eukaryotic Flagellum

Answer 33

Whiplike movement, powered by ATP hydrolysis, membrane bound, force generated by dynein

Question 34

Kinesin

Answer 34

Positive end directed motor protein, hand over hand (monkey bar) movement

Question 35

Dynein

Answer 35

Negative end directed motor protein

Question 36

Microfilaments (Actin Filaments)

Answer 36

Polymer of actin monomers forming a twisted rope, responsible for tension resistance and movement

Question 37

Sarcomere

Answer 37

Contractile unit of muscle

Question 38

Myosin

Answer 38

Motor molecule, has 2 actin binding heads and moves using a hopping motion

Question 39

Nuclear Lamina

Answer 39

Maintains structure of nucleus, found on inside of inner membrane

Question 40

Intermediate Filaments

Answer 40

Rope-like polymers formed by many different monomers, not very dynamic (no motor proteins associated), used for tension resistance

Question 41

Laminin

Answer 41

Forms the nuclear lamina, provides shape to nucleus, sits on inner face of inner nuclear membrane