Chapter 1 Flashcards
What three of ninety naturally occuring elements make up 98% of the atoms in any organism?
Hydrogen, Carbon and Oxygen
Why are hydrogen and oxygen so prevalent?
The ubiquity of water
-it exists everywhere and in everything
What element serves as the backbone of all organic molecules and why?
Carbon
-Strength and stability of carbon-carbon bonds
What are the four major classes of biomolecules?
-Proteins: C,H,O,N,S
-Nucleic Acids: C,H,O,N,P
-Lipids: C,H,O,N,P
-Carbohydrates: C,H,O and sometimes N,S
What are proteins and their functions?
-Constructed from 20 building blocks called amino acids, linked by peptide bonds to form long unbranched polymers
-Serve as signal molecules and receptors for signal molecules
-Play structural role, allow mobility and provide defenses against environmental dangers
-Most prominent role of proteins is that of a catalyst: enzymes that enhance the rate of chemical reaction without being permanently affected themselves
-Most proteins fold into 3D shape or structure to carry out function
What is protein folding?
-Driven by an entropic process called “the hydrophobic effect”
-Protein side chain atoms with hydrophobic character do not like to interact with water and self-associate to from the hydrophobic interior of a protein
What is nucleic acid?
-Primary function is to store and transfer information
-Contain instructions for all cellular functions and interactions
-Linear molecules constructed from four building blocks called nucleotides (five-carbon sugar and deoxyribose or ribose attached to a heterocyclic ring structure (base) and at least one phosphoryl group)
What are the two types of nucleic acids?
Deoxyribonucleic acid (DNA):
-Consists of a double helix of polymers made up of deoxyribose; phosphate and four bases (A, G, C, and T) where A-T and G-C
Ribonucleic acid (RNA):
-normally single-stranded polymer made up of ribose; Phosphate and bases A, G, C, and U
What is mRNA?
-Some regions of DNA are copied as a special class of RNA molecules called messenger RNA
-Template for the synthesis of proteins
-Frequently broken down after use
What is ATP?
-Source of Adenosine in RNA and deoxyAdenosine in DNA
-Used to fuel most biological processes requiring energy
-Synthesize roughly our body weight of ATP every day
What are lipids?
-Storage form of fuel and serve as a physical barrier for cells and organelles
-Key property is that they have both hydrphilic and hydrophobic properties
-Form barriers called membranes that allow compartmentalization
-Fuel molecules and signal molecules
What are carbohydrates?
-Important biological fuel source
-Glucose is common: stored in polymeric form as glycogen in animals
-Signaling molecules, notably in cell-cell recognition in animals
What is the central dogma?
-Scheme that underlies information processing at the level of gene expression
-Information flows from DNA to RNA and then to protein
-DNA can be replicated
Explain the basic principles of biological information transfer (central dogma)
DNA replication:
-DNA is heritable information (the genome)
-Replicated by a group of enzymes collectively called DNA polymerase
Transcription:
-RNA polymerase catalyzes transcription (process of converting DNA information to RNA)
-Selective transcription of the genome defines the identity and function of a cell or tissue
Translation of mRNA into protein:
-Converts the nucleic acid sequence information of messenger RNA into protein sequence information
-Occurs within ribosomes
-Genetic code specifies which base triplet encodes an amino acid (more than one triplet can encode a particular amino acid)
-Stop codons specify the end of a gene
What are the two biochemical features that minimally constitute any eukaryotic or prokaryotic cell?
-A barrier that separates the cell from its environment
-An inside that is chemically different from the environment and accommodates the biochemistry of living (plasma membrane)
