MCAT Sections 1-5 - Sciences
Ligase
A + B → AB + H2O
Oxidoreductase
A + B: → A: + B
Transferase
A + Bx → Ax + B
Hydrolase
A + H2O → B+C
Tetrad
A chiasma between a pair of homologous chromosomes resulting in the formation of 4 chromatids.
Synaptonemal Complex
A complex of proteins that are located between pairs of homologous chromosomes
Bottleneck Effect
A disaster causes a huge decrease in the population and a depletion of the gene pool
Recessiveness
A feature of an allele that will only produce a phenotype in the homozygous condition, normally masked by dominant trait.
Wild-Type
A gene that prevails among individuals in natural conditions
Gene
A position within a DNA sequence that codes for a specific trait
Glycolysis
A process that involves the investment of glucose to create 4 ATP, 2NADH, and 2 pyruvate. In red blood cells, this is the only form of energy production available.
Missence Mutation
A small single AA mutation in the DNA
Isomerase
A → B
Lyase
A → B+C
Incomplete Dominance
Alleles that are mixed together and express a new phenotype
Competitive Inhibitor
Alter Km, not Vmax
Non-competitive Inhibitor
Alter Vmax, not Km
Allele
Alternative forms of a gene for each variation of a trait of an organism.
Uncompetitive Inhibitor
Alters both Km and V max
Double Crossover
An event that suggests one of three outcomes: 1) Chromatids exchange alleles, then exchange back (no R) 2) Chromatids Exchange alleles, then exchange with different chromatids (R) 3) Chromatids exchange alleles, then two different chromatids on the same chromosome exchange again.
Extranuclear Inheritance
Describes situations where genes are inherited outside of the nucleus. This includes receiving all the information about the mitochondria from the mothers egg
Y Chromosome
Does not carry a lot of genes, but does have the SRY gene for creating testes.
Linkage
Genes located near to one-another on the same chromosome are likely to be inherited together.
The Oxidative Stage of the Pentose Phosphate Pathway
Glucose-6-Phosphate is oxidized to a lactone and then a Ribulose is created.
Independent Assortment
Happens during Meiosis I when homologous chromosomes randomly align on the metaphase plate.
Heterozygous
Having different copies of two alleles
Homozygous
Having the same copy of two alleles
Reproductive Isolation: Prezygotic
Isolation can result from temporal/Habitat Isolation, Behavioral isolation, zygotes not forming, and mechanical isolation
D-Fructose
Ketose of Glucose. Phosphorylated by fructokinase to trap in the cell. Cleaves into glyceraldehyde and DHAP.
Rewards from the Pentose Phosphate Pathway
Loss of H₂O and 2NADP⁺ to create Co₂, 2NADPH⁺, and Riobse-5-Phosphate
X Chromosome
Mom always donates, it also contains the genes for colorblindness and hemophilia.
Carcinogen
Mutates the DNA as to produce a cancerous phenotype.
Single Crossover
Occurs during prophase I and suggests that chromatids exchange alleles at a locus
Co-Enzymes
Organic Carrier molecules
Co-Factors
Participate in Catalysis, and inorganic
Genetic Drift
Random changes in a population
Adaption
The change of gene alleles over time to adapt to a specific environment
Fitness
The concept of how traits can produce an ability to survive.
Founder's Effect
The effect of founding a new population elsewhere which eliminates a lot of genetic variation
Expressivity
The extent to which you express your genes.
Phenylketoneuria
The inability to process phenylalanine
The Pituitary Gland
The master gland divided into two parts. The anterior pituitary secretes FSH, LH, ACTH, TSH, GH, and Prolactin.
Leakage
The movement of genes from one species to another (usually just one gene)
Phenotype
The physical characteristic trait that is displayed
Natural Selection
The process of one trait being favored over another, and thus producing offspring that are more likely to survive. This is ultimately through the ability to create children and mate.
Gluconeogenesis
The process of taking pyruvate molecules and creating glucose. 2 pyruvates, 2 ATP, HCO₃⁻, GTP, and NADH create GDP, 2ADP, 1Glucose, CO₂, NADH⁺
Hybridization: Viability
The process of two complementary, single-stranded DNA or RNA combining together, producing a double-stranded molecule through base pairing. This technique is used for interbreeding between individuals of genetically distinct populations.
Gene-Mapping
The process of using allele recombination frequency to determine how close alleles are to other alleles in test crosses.
Locus
The specific position on a DNA strand that codes for a specific genes.
Complete Dominance
The trait that completely masks the recessive allele.
Modern Synthesis Model
This adds knowledge of genetic inheritance and changes in the gene pool to Darwin's model. Specifically, that inheritance occurs through the passing of genes from parent to child, and that genes ultimately change due to mutation or recombination.
Penetrance
This is the percentage chance that you'll express the traits of a certain gene
Phenylalanine, Phe, F
aromatic, non-polar
Tryptophan, Trp, W
aromatic, polar
Tyrosine, Tyr, Y
aromatic, polar
Maltose
glucose + glucose
Fecundity
how well an organism can mate with another
Valine, Val, V
non-polar, aliphatic
Proline, Pro, P
nonpolar, aliphatic, Imino acid
Arginine, Arg, R
positively charged, basic
Lysine, Lys, K
positively charged, basic
Exergonic
release energy
Endergonic
require energy which is then stored in the chemical bonds
Le Chatelier's Principle
states that if a system at equilibrium is subjected to a stress the equilibrium is shifted to relieve stress
Cysteine, Cys, C
sulfur containing
Methionine, Met, M
sulfur containing
D-Mannose
"Gun"
Glycolysis/Gluconeogenesis Irreversible Enzymes
1) Hexokinase/Glucose-6-phosphatase 2) Phospho-Fructo-kinase 1/fructose-1-6-bisphosphatase 3) Pyruvate Carboxylase/PEP carboxykinase and pyruvate Kinase
ATP
Adenosine triphosphate, a molecule consisting of adenine, a sugar, and three phosphate groups that can be hydrolyxed to release free energy. Universally used by cells to store and transfer energy.
Inbreeding
Breeding from closely related people or animals, especially over many generations.
D-Galactose
C4 Epimer of Glucose. This sugar reaches the liver through the hepatic portal vein. It is phosphorlyated there and epimerized to glucose.
Reproductive Isolation: Postzygotic
Either the gametes cannot develop or one of the individuals is sterile.
Convergent Evolution
How a trait develops separately in two different populations
Divergent Evolution
How a trait is developed and the population separates
D-Glucose
If the last OH is on the right side, then the molecule is "D". "F*ck"
Testcross
Mating two different allele-carrying parents in order to determine what their genotypes are.
Hardy-Weinberg Principle
Measures the allele frequency of both the homozygous and heterozygous alleles in a population. p^2 + 2pq + q^2
Mutagen
Mutates the DNA in some fashion.
Pentose Phosphate Pathway
Occurs in the cytoplasm of most cells, generating NADPH and sugars for biosynthesis
Monosaccharide
One single subunit of a sugar
Thyroid
Promotes metabolism through T₃ and T₄ Precursors
Equilibrium Constant
Ratio of concentrations of the products to the concentrations of the reactants at the point of equilibrium, where each reactant and product in the expression is raised to the power of its stoichiometric coefficient. Commonly denoted by Keq.
The Non-Oxidative Stage of the Pentose Phosphate Pathway
Ribulose-5-Phosphate → Ribose-5-Phosphate → 10 carbon Ribose→ 3 carbon pyruvate/7 carbon molecule.
Co-Dominance
Situation in which both alleles of a gene contribute to the phenotype of the organism
Glycogen
Storage polysaccharide found in animals; composed of glucose molecules joined in a linear fashion but having numerous branches. This is stored in the cytoplasm as granules. Each granule has a central protein cores, and granules composed entirely of linear chains have the highest density of glucose near the core.
Gene Pool
The Sum of all genes/alleles in a population at a given time. High ratings have more genetic diversity and more fitness.
Genotype
The actual alleles carried by the individual
Fermentation
The anaerobic process in bacteria/lactic acid in humans that created pyruvate, NAD molecules, and energy. The main enzyme in this reaction is lactate dehydrogenase.
Free Energy
energy that is available to do work. Negative values stipulate spontaneous reactions.
Aspartic acid, Asp, D
negatively charged, acidic
Glutamic acid, Glu, E
negatively charged, acidic
Alanine, Ala, A
non-polar, aliphatic
Glycine, Gly, G
non-polar, aliphatic
Isoleucine, Ile, I
non-polar, aliphatic
Leucine, Leu, L
non-polar, aliphatic
Asparagine, Asn, N
polar, uncharged
Glutamine, Gln, Q
polar, uncharged
Serine, Ser, S
polar, uncharged
Threonine, Thr, T
polar, uncharged
Histidine, His, H
positively charged, Basic
