Unit 1 Terms

Question 1

Lipids

Answer 1

high molecular weight molecules soluble in nonpolar solvents

Question 2

Proteins

Answer 2

• large biomolecules and macromolecules that comprise one or more long chains of amino acid residues.
• diversity of structures, resulting in a wide range of functions
• everything in a cell is mediated
  by proteins
• made up of 20 amino acids, which have different physical and chemical properties

Question 3

Polysaccharides

Answer 3

• long-chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic bonds.
• storage or structural molecules

Question 4

Nucleic acids

Answer 4

• DNA and RNA
• Nucleic acids are macromolecules that exist as polymers called polynucleotides. The monomers are called nucleotides.

Question 5

Triacylglycerols

Answer 5

made up of one Glycerol molecule and 3 fatty acids

Question 6

Phospholipids

Answer 6

• hydrophilic “head” containing a
  phosphate group and two hydrophobic “tails” derived from fatty acids
• main components of cell membranes
• addition of R group makes t hydrophilic, allowing mixing of H2O and composing membranes
• Enzymes that metabolize phospholipids are in ALL membranes but never in the cytosol

Question 7

Amphipathic

Answer 7

having both hydrophilic and hydrophobic parts.

ex: phospholipids

Question 8

Disaccharides

Answer 8

two monosaccharides joined by a
glycosidic bond.

Question 9

Cellulose

Answer 9

structural polysaccharide of the cell wall of green plants

Question 10

Chitin

Answer 10

long-chain polymer of N-acetylglucosamine and the main component of insect exoskeleton

Question 11

amino acid

Answer 11

• is an organic molecule with both an amino group and a carboxyl group
• side chain varies
• made up proteins

Question 12

polypeptides & peptide bond

Answer 12

• Polypeptides are Amino Acid Polymers
• peptide bond: covalent bond between amino acids

Question 13

nucleotide

Answer 13

• is composed of three parts: a
  nitrogenous base, a five carbon sugar, and one phosphate group
• monomers

Question 14

pyrimidines vs purines

Answer 14

• nitrogenous bases
• pyrimidines: C, T & U
• purines: A & G

Question 15

DNA vs RNA

Answer 15

• DNA: Cytosine, Thymine, Adenine ,
  and Guanine
• RNA: Cytosine, Uracil, Adenine , and Guanine

Question 16

Three Polymerases

Answer 16

1. RNA polymerase I : rRNA genes,
2. RNA polymerase II : mRNA, miRNA, snRNA, and snoRNA genes
3. RNA polymerase III : tRNA and 5S rRNA genes

Question 17

Start/stop codons

Answer 17

• The start codon is the first codon of a mRNA transcript translated by a ribosome. Stop codon signals the termination of the translation process

Start codon = methionine
Stop codon = no aa
- There is no stop tRNA but a protein
that stops translation (translation termination factor)

Question 18

Spliceosomes

Answer 18

cut up the exons and reconnect them to produce the mRNA molecules that are used to make proteins.

Question 19

Translocases (think membranes & lipids)

Answer 19

proteins that move phospholipids between layers and maintain the lipid asymmetry

Question 20

FRAP (Fluorescence recovery after photobleaching)

Answer 20

method to study the mobility of molecules in living cells

Question 21

Crossing membranes (which can/cannot)

Answer 21

Can diffuse freely
- Small uncharged molecules

Can’t diffuse freely
- Large polar molecules
- Charged ions

Question 22

symporters vs antiporters

(facilitated diffusion, carrier exs)

Answer 22

• symporters transport two molecules in the same direction
• antiporters move two molecules are transported in opposite directions

Question 23

coenzymes

Answer 23

organic molecules that bind to the active sites of certain enzymes (ex: NAD, FAD)

Question 24

kinase

Answer 24

enzyme that phosphorylates

Question 25

Dehydrogenases

Answer 25

enzymes that remove a pair of hydrogen atoms from a substrate (oxidizing it)

Question 26

cataplerotic pathways vs anaplerotic pathways (in TCA cycle)

Answer 26

cataplerotic pathways
- precursors for biosynthesis

anaplerotic pathways
- regenerate the TCA intermediates

Question 27

coenzyme Q (in ETC)

Answer 27

lipid-like carrier that helps in ETC complex I carrying 2 e- from NADH..also helps in complex III carrying 2 e- before passing to cytochrome C

Question 28

Caspase 9 vs caspase 3 in apoptosis proteolytic cascade

Answer 28

Caspase-9: initiator caspase
- begin the apoptotic program by activating the executioner caspases, which mediate the apoptosis program
- inactive monomers that activate when they dimerize and self cleave

caspase 3: effector caspase
- cleaved and activated by initiator caspases
- executioner caspases have shorter prodomains

Question 29

Ferroptosis

Answer 29

• intracellular iron-dependent form of cell death that is distinct from apoptosis, necrosis
• characterized by accumulation of oxidatively damaged phospholipids (lipid peroxidation)