Midterm 1 (chapters 1-6) Flashcards
What are the 5 fundamental characteristics of life?
Energy, genetic information, cells, replication, evolution
What are the three main theories in biology?
evolution, chromosomal theory, cell theory
What is the cell theory? Who is associated with it?
Dr. Virchow; all organisms are made of cells & cells come from pre-existing cells
What is the theory of evolution? Who is associated with it?
Darwin; species are related by common ancestors. species characteristics modified from generation to generation.
What is the chromosomal theory? Who is associated with it?
Sutton & Boveri; hereditary information is encoded in genes found in chromosomes (your traits come from your parents)
What is the order of the central dogma of molecular biology? (DNA to traits)
DNA -> mRNA -> proteins
What did Dr. Woese do?
created phylogeny= evolutionary relationships between species (he compared RNA relatedness between organisms to create a phylogenetic tree), & he defined the 3 domains of life= bacteria, eukaryote & archaea
What are the common elements of life?
carbon, hydrogen, oxygen & nitrogen
What is the structure of an atom
protons & neutrons in nucleus, electrons on the shells
What is a proton?
has a positive charge, located in nucleus, & it’s the atomic number which doesn’t change
What’s an electron?
has a negative charge, located on the shells, elements need to be stable so they will share / gain or lose electrons to reach the octet rule (8 in valence shell, 1st shell only needs 2 electrons)
What is the valence shell? What is the valence number?
Valence shell= outermost shell & Valence number= number of unpaired electrons in the valence shell
What are the 3 kinds of bonds?
covalent, ionic, hydrogen
What is a covalent bond?
forms when atoms share electrons in order to satisfy the octet rule (if carbon has 4 electrons, and hydrogen has 4 electrons = methane)
What is an ionic bond?
forms when atoms are held together by the attraction between the opposite charge (ex: sodium chloride: chloride has 7 electrons (slightly negative bc gained an electron), sodium has 1 electron (slightly positive bc one electron lost) -> table salt)
What is a hydrogen bond?
caused by polar covalent bonds if those partical charges are opposite
What is the difference between polar & non-polar?
polar has a charge & nonpolar doesn’t have a charge
What is the difference between hydrophobic & hydrophillic?
hydrophobic= has a charge (polar), water soluble, lipophobic (doesn’t like lipids)
hydrophillic= no charge (non-polar) , doesn’t like water (bc no charge), lipophilic (likes lipids)
ex: water (polar) + oil (non-polar) = doesn’t mix because oil is hydrophillic
What are the properties of water?
water can be used as a solvent (the ability to dissolve other substances in a solution), 75% of a typical cell volume is water. Solid water is less dense so it can float on water. Life thrives with water.
What is the difference between cohesion & adhesion?
Cohesion= water is attracted to water (other hydrogen bonds)
Adhesion= water is attracted to other charged/polar molecules
What is electronegativity?
Formula: O>N>S=C=H=P
when shared electrons in a bond are pulled towards the nucleus
What chemical reaction puts all 4 of the macromolecules together?
dehydration/condensation
What chemical reaction separates all 4 macromolecules?
hydrolysis (water is added to break poly into mono)
What is the basic chemical structure of an amino acid?
an amino group, central carbon, hydrogen, carboxyl group, r-group (only thing that changes between all the amino acids)
What are the 4 levels of protein structure?
primary= sequence of amino acids
secondary= what’s in common with the amino acids (the backbone)
teritary= the r-group
quaternary= proteins binding to other proteins (like hemoglobin)
What is sickle cell?
changes the 6th amino acid to valence (unable to hold oxygen)
What are the 4 groups of amino acids?
polar, non-polar, positive charge, negative charge
What is a non-polar amino acid?
all have non-polar covalent bonds (hydrophobic), no presence of oxygen (O) or nitrogen (N) b/c they are electronegative
What is a polar amino acid?
hydrophilic, has electronegative elements like oxygen & nitrogen so it has a partial charge
What is a negatively charged amino acid?
has a negative charge (can see it on diagram)
What is a positively charged amino acid?
has a positive charge (can see it on diagram)
What are the 3 parts of a nucleotide?
nitrogenous base (A,T,G,C) + sugar (glucose) + phosphate group
What are pyrimidines? Purines?
pyrimidine= cytosine & thymine
purines= adenine & guanine
Which nucleotides bind together?
A+T
G+C
What are the differences between RNA & DNA?
- DNA is a double stranded helix (constant in structure) & RNA is single stranded so it can fold over to create different structures
- DNA has thymine (A+T) while RNA has uracil (A+U)
- DNA has deoxyribose which has an absence of one oxygen molecule & RNA has ribose which has that extra oxygen molecule thats why DNA is called deoxyribonucleic acid & RNA is called ribonucleic acid
- DNA just carries genetic traits while RNA is multifunctional (can be an enzyme)
What did Watson & Crick do?
they took what Chargaff & Franklin discovered, and found that DNA is an anti-parallel double-stranded helix
What does DNA replication achieve?
reproduction of cells, creates proteins which determine physical traits
What is a monosaccharide? Disaccharide? Polysaccharide?
mono= 1 sugar
di= 2 sugars
poly= multi-sugars
What are the 3 main monosaccharides?
glucose, fructose, galactose
What are the 3 main disachharides?
sucrose= glucose + fructose
lactose= glucose + galactose
maltose= glucose + glucose
What are the 5 main polysaccharides?
starch= stores energy in plants
glycogen= stores glucose energy in animals/humans
cellulose= support for plants
chitin= support for insects & crustaceans (in their exoskeletons)
peptidogylcan= support for bacteria
What are the covalent bonds called in all 4 macromolecules?
amino acids= peptide bonds
dna= phosphodiester bonds
carbohydrates= glycolistic linkage
lipids= ester linkage
What are healthy fats vs unhealthy fats?
saturated fats= unhealthy
unsaturated fats= healthy
What are saturated fats?
- straight & closely packed
- unhealthy
- solid at room temp
- blocks arteries & stays solid in the bloodstream can lead to heart attack or stroke
What are unsaturated fats?
- has a kink to it
- liquid at room temp
- healthy
What is a lipid? What is a phospholipid?
Lipid= 3 fatty acids + glycerol
Phospholipid= has a hydrophilic head (phosphate & glycerol), 3 fatty acids (saturated and/or unsaturated) [hydrophobic tail]
What is the layers of lipids?
extracellular space= hydrophilic head
phospholipid bilayer= 2 layers of phospholipids w hydrophobic interior & hydrophilic exterior
cytoplasm= hydrophilic head
What are the characteristics of the phospholipid bilayer?
-it has selective permeability, allows certain things into our cells
-high selective permeability= gases (CO2 & N2)
-low selective permeability= ion with a charge to it (bc the tails are hydrophobic so it has no charge to it so it won’t allow charged ions in)
-its affected by the temperature
-increase= more fluidity / movement
-decrease= less movement -> freezes
What is diffusion?
the random movement of molecules from high concentration to low concentration until equilibrium (equal concentration) is reached [doesn’t need energy]; can’t happen with every molecule
What is osmosis & tonicity?
osmosis= diffusion of water across semipermable membrane
tonicity= determines the direction in which osmosis occurs
The effects of hypertonic, hypotonic & isotonic solutions
water moves from hypotonic to hypertonic or from high to low. water follow the ion concentration between the membrane. while others follow its own concentration.
hypertonic= a solution with greater solute concentration than that in another solution
hypotonic= a solution with lower solute concentration than that in another solution
isotonic= a solution with same solute concentration than that in another solution
