Quiz 1 Flashcards
Cell Theory
Cells are units of life; living organisms made up of cells, smallest unit of living organism, come from other cells (structure depends on matter, energy, organization, information
Prokaryote
Doesn’t have nucleus, “simple” structure (bacteria, archaea)
Eukaryote
Does have nucleus and membrane-bound organelles; “complex” structure (protists, plants, fungi, animals)
General structure of bacterium
Nucleoid, chromosomes, cytoplasm, ribosomes, flagella, three coverings (glycocalyx that traps water, cell wall that offers structure, and plasma membrane that encloses it)
Organelle
Intercelllular component that performs distinct function (membrane bound or no membrane)
Genome
Genes; all DNA that you have, contains info used to make proteins
Proteome
Made up of amino acids and are expressed forms of genes; can be structural or functional (all cells have full copy of genome but different proteomes
Differences in proteomes between cells can be due to:
Proteins are unique to certain cell types, proteins can be expressed at different levels, differential splicing, post-translational modifications
Plasma membrane
Enclosed cell; interface between cell and its environment (selectively permeable, maintains differences between environments outside vs. inside cell
Structure: lipid bilayer, membrane proteins
Functions: membrane transport, cell signaling, cell adhesion
Cell coat
Covers plasma membrane, composed of sugars, protects cell
Cytoplasm
Everything inside cell minus nucleus
Cytosol
Liquid part of cytoplasm (50% volume)
Functions: metabolism, signaling pathways
Cytoskeleton
Network of filaments (protein fibers) in cell; motor proteins
Structure: fibers are made of proteins (actin filaments, microrubules, and intermediate filaments)
Functions: cell organization, shape, movement, strength
Ribosomes
Located in cytosol and membranes
Structure: two subunits made of protein and RNA
Function: translates proteins by means of genetic code stored in mRNA
Proteasome
Not membrane bound, made of proteins; digests proteins–recycle!
Centrioles and centrisome
Centrioles composed of protein, compounds if centrosome; where microtubules eminate from
Nucleus
Structure: nuclear envelope (inner membrane, perinuculeur space, and outermembrane), nucleur pores
Functions: stores and expresses genetic info
Nucleolus
Structure: no membrane, large aggregate of macromolecules in nucleus
Function: ribosome factory
Endoplasmic reticulum
Rough ER contains ribosomes and smooth ER doesn’t
Structure: single membrane with ER lumen inside
Function: RER is where proteins are synthesized and processed then transported in vesicles to GA, SER detoxifies, stores Ca, and synthesizes lipids
Golgi apparatus
Structure: stack of 4-6 flat membrane enclosed compartments called cisterna; three distinct compartments (cis golgi network, cis/medial/trans cisterna) and trans golgi network
Functions: major site of carb synthesis; processing and pack and tag
Lysosome
Structure: single membrane, contains acid hydrolases
Functions: breakdown of macromolecules to components
Mitochondrion
Endosymbiotic hypothesis: used to be bacteria then engulfed by primitive eukaryotic cell
Structure: outer membrane, intermembrane space, inner membrane with folds called cristae; mitochondrial matrix
Functions: produces ATP by cellular respiration, apoptosis
Peroxisomes
Structure: small, single membrane, matrix
Function: oxidate chemical reactions, breakdown fatty acids, endogeneticd source of DNA damage
Four characteristics of genetic materi
Replicate, store information, express information, allow variation by mutation
Central dogma of molecular genetics
DNA -> RNA -> protein
Fredrich Miescher
(1868) first one to discover DNA, called it nuclein
Phoebus A. Levene
(1910) DNA contains four different components (A, T, C, and G)
Tetranucleotide hypothesis
One unit contains all four linked nucleotides, ATCG, over and over identically/equally
Edwin Chagraff
(1940s) showed all four components are not present in equal amounts in DNA (A=T, G=C)
Griffith experiment
Experiment with pneumonia in which some harmless strands IIR and some heat-killed virulent strands IIIS were injected into a mouse and it DIED and live IIIS cells were found
Griffith called it transformation but didn’t know it was DNA
Avery MacLeod and McCarty experiment
Showed substance was DNA by ruling out proteins and RNA by rupturong heat killed bad guys and filtering out everything but the DNA, RNA, and proteins, THEN add no treatment, protease, ribonuclease., and deoxyribonuclease to different tubes and add living IIR bacteria to see which one still made them IIIS
Henry-Chase experiment
Additional evidence that DNA is genetic material by using T2 bacteriophages (50% protein 50% DNA) with either radioactive sulfur (in protein) or phosphorus (in DNA) to inject e coli bacteria and whichever one appeared was the substance that was genetic code
Protoplasts
Bacteria with outer cover removed
Indirect evidence that DNA is genetic material
Distribution of DNA (found only in nucleus rather than everywhere like protein) and mutagenesis (UV light produces mutations at 260nm; DNA absorbs at 260nm while protein absorbs at 280nm)
Direct evidence
Recombinant DNA technology (genetic engineering)
Three components of a nucleotide
Sugar, nitrogenous base, phosphate group
Pentose sugar in DNA and RNA respectively
Deoxyribose (H on C2) and ribose (OH on C2)
C1 is the carbon on a pentose sugar to which
the nitrogenous base is bonded
C3 is the carbon to which
OH is bonded
C5 is the carbon to which
The phosphate group is bonded
Two classes of nitrogenous bases
Prunes (adenine and guanine) and pyrimidines (cytosine, thymine-DNA ONLY, and uracil-RNA ONLY)
Similarities and differences between nucleotides in DNA
All contain same type of sugar and phosphate group, but can contain four different bases
Nucleotide names based on number of phosphate groups
NMP (one phosphate) NDP (two) NTP (three)
A nucleoside is composed of
A base and a sugar
Nucleotides are linked together by means of a
Phosphodiester bond
A chain of nucleotides has
A 5’ and a 3’ end; oligonucleotide chains have fewer than 15-30; polynucleotides have more
What did Changraff show about DNA compositon?
A=T and C=G, so ex: 15% A means 15% T and 35% C and 35% G
Rosalind Franklin
Found DNA was helix
Watson and Crick
Found DNA wad a double-stranded, right-handed helix that runs in an anti-parallel fashion with major and minor grooves
Complementary nature of base pairs
Any base pair is composed of a purine and a pyramidine to ensure diameter is always 20 Å (A bonds with T which is a two hydrogen bond and C bonds with G which is a three hydrogen bond)
Sugar-phosphate backbone of a DNA molecule
Sugars and phosphates face outside of helix, wrapping outside of DNA
How is DNA is a stable structure
it has many base pairs so many hydrogen bonds and because of hydrophobic and hydrophilic interactions
A-DNA and B-DNA are both
right handed (only Z-DNA is lefthanded)
Differences between RNA and DNA
The sugar is ribose in RNA (rather than deoxyribose), the pyrimidine base is U instead of T, and RNA is single stranded; a secondary structure in RNA is a region that is double stranded because of base pairing
Three major classes of RNA
messenger RNA (mRNA, 5% of RNA in e coli), ribosomal RNA (rRNA, 80% in e coli), and transfer RNA (tRNA, 15% in e coli)
