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