Cell functions

Question 1

Enzymes

Answer 1

Functional proteins. Chemical catalysts reducingactivation energy needed fro a reaction. Regulate metabolic pathways - specific to one substance - inhibited or activated by various physical and chemical agents

Question 2

Cellular respiration review

Answer 2

1 glucose (C6H12C6) — glycolysis in cytosol
—>
2 pyruvic acid + oxygen — citric acid cycle and ETC in mitochondrion
—>
CO2 + H2O + 36 or 38 ATP

Question 3

Anabolism

Answer 3

Protein synthesis - begins with genetic master code in cell’s DNA - influences all cell structures and functions

Question 4

Cell reproduction

Answer 4

Mitosis: Cell reproduce by splitting themselves into two smaller daughter cells - each cell must contain sufficient cytoplasm (including mitochondria and other organelles) as well as complete set of genetic information

Question 5

Allosteric effector

Answer 5

Alters enzyme function by changing its shape - may inhibit or activate enzymes by altering shape of active site - includes antibiotic drugs, changes in pH, changes in temperature, and cofactors

Question 6

Glycolysis without oxygen

Answer 6

Pyruvate acid molecules will follow the anaerobic pathway to form lactic acid - as oxygen becomes available, lactate converts back to pyruvate or even glucose

Question 7

Glycolysis

Answer 7

Glucose break down to form 2 Peruvian acid molecules - occurs in cytosol, outside of any organelle - anaerobic reaction - produces 2 ATP

Question 8

Sodium-potassium pump

Answer 8

• 3 Na+ in cytosol bind to pump proteins, which triggers ATP ydrolysis
• shape of protein changes and 3 Na+ are deported into ECF
• 2 K+ then bind, trigger ATP hydrolysis, protein changes shape and 2K+ desposited into cell, protein shape now ready for 3Na+

Question 9

Active transport

Answer 9

Requires expenditure of metabolic energy by the cell. Transport by pumps and vesicles. Moves up concentration gradient

Question 10

Exocytosis

Answer 10

Processs by which large molecules (proteins) can leave the cell when they are too large to move out throug the cell membrane. Also provides a way to add new plasma membrane

Question 11

Meiosis

Answer 11

Cell division that occurs only in primitive sex cells during the process of becoming mature sex cells with 23 chromosomes

Question 12

Isotonic solution

Answer 12

Cell stays the same size because there is no net movement of H2O into or out of the cell

Question 13

End product inhibition

Answer 13

When a chemical product at the end of a metabolic pathway binds to the allosteric site of one or more enzymes along the pathway that produce it in order to inhibit synthesis of more product (negative feedback)

Question 14

Coenzyme

Answer 14

Organic non protein molecule that is a nonprotein cofactors.

Question 15

Diffusion

Answer 15

Movement of solute down concentrartion or electrical gradient. Stops when reaches equilibrium

Question 16

Osmosis

Answer 16

Movement of water through a semi-permeable membrane down concentration gradient. Particle movement is limited, so water moves. Aquaporins allow movement through phospholipid membranes

Question 17

Passive transport

Answer 17

Does not require energy expenditure or activity from membrane. Stuff moves down a concentration or electrical gradient
- diffusion - osmosis - osmotic pressure - channel mediated passive - carrier mediated transport

Question 18

Hypotonic solution

Answer 18

Causes the cell to swell as H2O moves into it. Cell may burst (lyse)

Question 19

Carrier mediated transport

Answer 19

Facilitated diffusion of solute through a membrane by a carrier. Open on one side, solute enters and binds, it closes and opens the other side. Can be reversible.

Question 20

Transport by pumps

Answer 20

Driven by energy from hydrolysis of ATP and energy stored in an ionic concentration gradient - utilizes carrier proteins - most prevelant is sodium-potassium pump.

Question 21

Metabolic pathways

Answer 21

Chemical reactions that occur in a sequence of reactions, requires enzymes

Question 22

Hypertonic solution

Answer 22

Causes cell to shrink as H2O moves out. Cell may be permanently damaged and die.

Question 23

Receptor-mediated endocytosis

Answer 23

Receptors in plasma membrane bind to specific molecules in ECF, which triggers endocytosis

Question 24

Cell metabolism

Answer 24

Set of chemical reactions of a cell

Question 25

Phagcytosis

Answer 25

Cell engulfs large solid particles (whole bacteria, viruses, worn out cells) and the vesicles fuse with lysosomes that break down unwanted material - undigested materials are secreted by exocytosis or reside within the cell in a residual body

Question 26

Citric acid cycle

Answer 26

Pyruvate acid from glucose is converted to acetyl coenzyme A (CoA) - occurs in the mitochondria of the cell (where enzymes are located) - produces CO2 + energy in the form of energized electrons

Question 27

Transport by vesicles

Answer 27

Substances dont actually go through the plasma membrane

Question 28

Genetic code

Answer 28

Dictates structures of each protein produced by the cell

Question 29

Pinocytosis

Answer 29

Cell drinking. ECF enters cell. Cell ingests fluid and solutes and then removes material from plasma membrane (receptors and channels). Cell can regulate membrane this way.

Question 30

Channel mediated transport

Answer 30

Facilitated diffusion of solute through a membrane channel. Gated channels open/close by various triggering mechanisms. Protein tunnels. Solute specific.

Question 31

Cell growth

Answer 31

Depends on using genetic info in DNA to make the structural and functional proteins needed for cell survival - Newly formed cell synthesize new molecules and organelles, including an extran set of DNA molecules in anticipation of reproduction

Question 32

Active site

Answer 32

Chemically fits the substrate on the enzyme. Thats where the magic happens

Question 33

Endocytosis

Answer 33

Traps extracellular material and brings it into the cell. Cytoskeleton forms vesicle. 3 types: receptor-mediated endocytosis, phagcytosis, and pinocytosis

Question 34

Equilibrium

Answer 34

Equal concentration. Not a static state without movement but a balanced state stat in which the number of molecules crossing the membrane is equal in both directions.

Question 35

Catabolism

Answer 35

Protein breakdown

Question 36

Osmotic pressure:

Answer 36

Water pressure that results from osmosis. Osmotic pressure is higher in the solution with higher concentration and this drives the water out.

Question 37

Catalysts

Answer 37

Participate in chemical reactions but are not themselves changed by a reaction

Question 38

Cellular respiration

Answer 38

Glucose —> CO2 + H2O + energy

Glycolysis + citric acid cycle + electron transport chain

Question 39

Electron transport chain

Answer 39

Energized e- are carried to specialized molecules embedded in the inner mitochondrial membrane - e- are shuttled along a chain of specialized molecules and cause protons to be pumped into intermembrane space - protons (H+) cross back through the inner mitochndrial membrane into inner chamber by way of reverse pump carriers - ATP synthase carriers convert the energy of passive proton flow into chemical energy which is transferred to ATP molecules - produces 34 ATP (along with citric acid cycle)

Question 40

Glycolysis with oxygen

Answer 40

Pyruvate acid molecules will follow the aerobic pathway and enter the citric acid cycle

Question 41

Kinases

Answer 41

Active enzymes, which are naturally inactive because they are synthesized as inactive proenzymes

Question 42

Transcription

Answer 42

Gene code in DNA is copied to messenger RNA (mRNA) in the cell nuclus - mRNA separates from the DNA strand and carries a “message” of gene code sequence to a ribosome in the cytoplasm - cell translates genetic code - tRNA transfers amino acids from cytoplasm to the ribosome - as amino acids are brought into place, peptide bonds join them to produce an entire protein (process of translation)

Question 43

Dynamic equilibrium

Answer 43

Condition of continual, constant diffusion