Lecture 17: Signal Transduction, ECM, Mitochondria

Question 1

Extracellular matrix (ECM) components..

Answer 1

Proteins, glycoproteins, proteoglycans - proteins with chains of polysaccharides

Question 2

Functions of the ECM (4)

Answer 2

• Cell adherence
• communication between cells
• cell shape, mechanical support, structural integrity
• serves as barrier, filter out some particles

Question 3

Anchor proteins role

Answer 3

• interacting with components of ECM
• helps with tissue formation and cell function
• communication between cells

Question 4

Example of ECM

Answer 4

Skin, cell walls (plants)

Question 5

What is signal transduction

Answer 5

Allows cells to rapidly respond to events happening in their environment, membrane proteins playa. Role in ST by converting extracellular signal to intracellular signals

Question 6

Signal transduction allows cells to: (5)

Answer 6

• grow
• divide
• survive (or not)
• move
• differentiate

Question 7

Ligand binding

Answer 7

Ligand binds to receptor on extracellular side, changes conformation of receptor protein in intracellular side of the cell which causes other proteins to be activated, doesn’t enter cell

Question 8

Signal transduction steps:

Answer 8

1. Binding of ligand to receptor
2. Signal transduction via second messengers like cAMP, calcium or G-protein
3. Cellular response: cellular growth, division, store glucose molecules

Question 9

Glycogenolysis

Answer 9

Enzyme that acts as primer to polymerize first glucose molecules

Question 10

Adrenaline (example of signal transduction)

Answer 10

Adrenaline activates conversion of glycogen stored in liver to glucose

Question 11

Main function of mitochondria (2)

Answer 11

• ATP synth
• apoptosis

Question 12

Main function of chloroplasts (2)

Answer 12

• photosynthesis
• ATP synth

Question 13

Endosymbiotic theory

Answer 13

Organelles from eukaryotic cells with two membranes, represent formerly free living prokaryotes (mitochondria and chloroplast) into the cell to create an ancestral eukaryote

Question 14

Supporting evidence of endosymbiosis theory

Answer 14

1. Binary fission
2. Circular DNA

Question 15

Energy supplies

Answer 15

1. Aerobic resp.: converts in the presence of oxygen energy stored in food molecules into chemical energy stored in ATP, produces CO2 and waste
2. Photosynthesis: building carbohydrates using energy from sunlight and CO2

Question 16

Mitochondria structure

Answer 16

• Outer Mitochondrial membrane (OMM)
• Inner mitochondrial membrane (IMM)
• aqueous compartments

Question 17

Mitochondria: OMM

Answer 17

• contains enzymes with diversity
• contains porins - large channels permeable (passive diffusion) to many molecules when opened

Question 18

Mitochondria: IMM

Answer 18

• 3 protein: 1 lipid
• double-layered folds called Chris yea; increase membrane SA and contain machinery for aerobic resp and ATP formation
• rich in phospholipid called cardiolipin; characteristic of bacterial membranes and needed for optimal function

Question 19

Mitochondria: Matrix

Answer 19

• high protein content
• gel-like space containing mitochondrial ribosomes and mitochondrial genome (DNA)

Question 20

What is cellular respiration?

Answer 20

• uses chemical energy stored in molecules such as carbs and lipids to produce ATP
• involves catabolic rxns
• cellular resp in presence of oxygen = aerobic respiration

Question 21

What is substrate-level phosphorylation

Answer 21

• hydrolysis rxn releases enough energy to drive phosphorylation of ADP to ATP

Question 22

What is oxidative phosphorylation?

Answer 22

• chemical energy of organic molecules is transferred first to electron carriers that is s used to create an electrochemical gradient that can power ATP synth

Question 23

Oxidative phosphorylation produces about ____ percent of ATP in animals cells

Answer 23

88

Question 24

NAD+ is _____ and NADH is ____

Answer 24

Oxidized, reduced

Question 25

FAD is _____ and FADH2 is ____

Answer 25

Oxidized, reduced

Question 26

Oxidative phosphorylation steps

Answer 26

1. Generate an electrochemical gradient: ET through complexes I-IV and proton (H+) pumping, high-energy electrons pass from coenzymes (NADH and FADH2) in the matrix to electron carriers in IMM, series of intermediate electron carriers is the ETC. energy transfer at each complex used to pump H+ from matrix to inter membrane space. Ultimately, low energy electrons are transferred to terminal electron acceptor (O2) resulting in production of H2O.
2. Proton movement down electrochemical gradient to power ATP synthesis

Question 27

Catabolism

Answer 27

Breaking down molecules

Question 28

Anabolism

Answer 28

Building up molecules

Question 29

Substrate-level phosphorylation takes place in the…?

Answer 29

Cytoplasm