Chapter 1: Biochemistry and the Unity of Life Flashcards
List the 4 major biomolecules
Proteins, Nucleic acids, Lipids and Carbohydrates
What is the central dogma of molecular biology?
DNA –> RNA –> Protein
Proteins
+ Highly versatile
+ constructed from 20 a.a.
- signal molecules + receptors for signaling molecules
- play structural roles: muscle, membrane and cytoskeleton
- Most prominent role is being a catalyst
Nucleic Acids
+store and transfer info
+linear molecules
-constructed from 4 nucleotides
-ATP
-informational biomolecules
DNA - comp
4 deoxyribonucleotides possible (base variability)
- adenine, guanine, cytosine, thymine
-double-helix
-phosphodiester linkages
RNA - comp
- single stranded
- contains additional OH group
-uracil replaces thymine
-mRNA copies DNA regions
Lipids
+smaller than protein & nucleic acids
+ lighter molecular weights
+ not polymers
- Dual chemical nature (hydrophobic and hydrophilic)
- barrier formation
-also store energy
-signaling molecule
hydrophobic component can undergo combustion to provide Energy
Carbohydrates
-important fuel source
- glucose is most common
- Role in cell signaling and cell recognition
+ carbs are linked together in highly branched chains (important for cell-cell comms.)
Glucose in plants vs animals
Plant - starch
Animal - glycogen
DNA replication steps
- replication:
DNA copied - catalyzed by DNA polymerase - transcription
copied genes are made accessible - DNA –> RNA, catalyzed by RNA polymerase
3.translation:
info encoded in mRNA is realized - nucleic acid –> protein
- occurs on ribosomes
Eukaryote
contain membrane-enclosed compartments
Prokaryote
simple structure
-2 membranes separates by periplasmic space
Microbiome
collection of organisms that live in a particular environment
Human microbiome
all microorganisms living in + on the human body
Microbiome disruption may cause development of….
Type II diabetes
Cardiovascular disease
Liver disease
Inflammatory bowel disease
Cell membrane
a lipid bilayer organized with chains and heads that separate environments
impermeable to most substances (fuels, signal molecules and building blocks)
Selective permeability
achieved by embedded proteins - facilitate entry of glucose, a.a. and info transduction
Cytoplasm
Site of many biochemical processes:
1. initial stage of glucose metabolism
2. fatty acid synthesis
3. protein synthesis
Cytoskeleton
network of structural filaments - 3 protein fibers:
1.actin filaments
2.intermediate filaments
3. microtubules
all support cell structure, localize biochemical activities + serve as molecular highways
Nucleus
- double-membrane bounded organelle
- info center - location of genome
+ porous membrane for transport
+ where molecular machines function
+ where genomic info is selectively expressed
Mitochondrion
+outer membrane touches cytoplasm
-inner membrane defines the matrix
+fuel molecules undergo combustion into CO2+H2O+ATP
+90% of Energy used by cell comes from
- energy production
Endoplasmic reticulum
+ series of membranous sacs where reaction take place (on cytoplasmic surface + lumens)
- Smooth ER –> processing exogenous chemicals
- rough ER: ribosomes produce membrane or secretory proteins
+Rough ER –> ribosomes synthesize proteins + translation in ER lumen + protein folding with chaperones + protein bud off RER as transport vesicles
Golgi complex
- Process proteins from RER
+transport vesicles from RER come to Golgi
+further procession occurs (glycosylation)
+Golgi sorts protein by function + future place
Exocytosis
secretory granules bud off Golgi and fuse with cell membrane for release/secretion of biomolecules
Endocytosis
entry of biomolecules (Fe, Vit B12, Cholesterol) into the cell
large molecules = phagocytosis
Endosome
Plasma membrane invaginates and buds off into cell
Lysosomes
-Formed by Golgi ->formation similar to secretory granules
-fuse with endosomes to digest ingested contents (degradation)
- also digest damaged intracellular organelles
Familial hypercholesterolemia
-can cause heart attacks is 6 yr olds
-poor endocytosis of cholesterol from the blood
Tay-Sachs disease
-destructive for neurons
-cause muscle weakness, dementia and death at an early age
-failure of lysosomes to function properly
buildup of sphingolipids
The biochemicals that make up 98% of humans
Hydrogen, Oxygen and Carbon
The biochemical that follow after the main 3
Nitrogen, phosphorus and sulfur
Silicon is more abundant than carbon but why is it not vital?
Si-Si bonds are weaker than C-C bonds
- C-C bonds used for strong backbones
- More Energy released from breaking C-C bonds
- oxidized silicon is insoluble in water
