Chapter 1 Flashcards
biochemistry
study of living organisms at the molecular level
eukaryotes
contain a membrane-enclosed nucleus
living cells require
- barrier that separates it from its environment
- interior that is chemically distinct from the surroundings
cellular membranes
two layers of lipids whose hydrophobic tails interact on the interior and whose hydrophilic heads interact with the environment
plasma membrane
selectively permeable to fuels, building blocks and signal molecules that must enter the cell
cytoplasm
- material that comprises the cell interior
- many biochemical processes including glucose metabolism, fatty acid synthesis, and protein synthesis
cytoskeleton
gives the cell its structure and serves as a system of “molecular highways” for materials transport throughout the cell
nucleus
information center of the cell and the location of the organism’s genome
mitochondria
ATP generation
endoplasmic reticulum
membranous sacs surrounding the nucleus
smooth ER
processes chemicals originating outside the cell, such as drugs
rough ER
ribosomes for protein manufacture are attached
golgi complex
stacked membranes that receive transport vesicles from the rough ER and processes the proteins for secretion of delivery to the plasma membrane
secretory vesicles
carry cargo of mature proteins to the plasma membrane
lysosome
digests material brought into the cell by endocytosis
chloroplast
found only in plant cells and is the site of photosynthesis
vacuoles
store water, ions, and various nutrients
cell wall
constructed from cellulose to form a protective wall around the cell
elements of life
hydrogen (63%), carbon (9%), and oxygen (25%)
why hydrogen and oxygen
H20 is matrix of life, polar molecule allowing it to self-interact and form weak bonds
why carbon
forms 4 covalent bond, C-C bonds release a lot of energy
stereoisomers
same atom connectivities but differ in arrangement
chiral
not superimposable on mirror images
enantiomers
a molecule and its non-superimposable mirror image
proteins
20 different monomer building blocks (amino acids)
N-terminus
(beginning) free amine (NH2) group
C-terminus
(end) free carboxyl (COOH) group
proteins are highly versatile
regulation, storage, motion, transport, defense, and structure
catalysts
agents that enhance the rate of a chemical reaction
protein catalysts
enzymes
nucleotide
five-carbon sugar attached to heterocyclic ring and a phosphoryl group
nucleotides are joined by
phosphodiester bonds to form linear molecules
DNA
stores genetic information
RNA
transfers information
carbohydrates
3-9 carbon atoms and simple sugars
carbohydrates are
fuel sources, signaling molecules
lipids
water-insoluble organic molecules, form barriers to protect the cell and its organelles
thermodynamics
system (any part under study)
surroundings (everything else)
open systems
exchange matter and energy
closed systems
exchange matter
first law of thermodynamics
energy can be converted but neither created nor destroyed
Enthalpy (ΔH)
heat evolved in a reaction at constant pressure
Entropy (S)
degree of randomness or disorder in a system
Gibbs Free Energy
ΔG = ΔH - TΔS
exergonic
negative ΔG (spontaneous)
endergonic
positive ΔG (nonspontaneous_
free enegry
energy is capable of doing useful work
central dogma
genetic information is stored in DNA and it can be replicated, and passed through an RNA intermediate before being expressed as a protein
replication
DNA acts as a template for the synthesis of new DNA
DNA polymerase
catalyze the replication process and duplicate the genome
transcription
DNA is used as a template for the synthesis of an RNA
RNA polymerase
catalyzes transcription
translation
messenger RNA copy is interpreted and used to drive the synthesis of protein
