Enzymes, DNA, and Inheritance

Flashcards covering key vocabulary and concepts from the lecture notes.

Enzymes

Enzymes end with ASE.

DNA Replication

Required for reproduction and growth and tissue replacement in multicellular organisms - Allows new cells to have the same instructions for transcription and translation as the old cells

DNA Helicase

Breaks hydrogen bonds in the middle of the two DNA strands

DNA polymerase

Builds new DNA using two separated parent strands as templates; always builds new DNA in 5’ to 3’ direction

Semi conservative replication

Conserves half of the original molecule; Half comes from the original ones and half is freshly build

PCR (Polymerase Chain Reaction)

Template: double-stranded dna that is copied. At high temps, DNA jiggles until the hydrogen bonds cannot be maintained, and therefore falls apart - almost to boiling point

Taq polymerase

Special DNA polymerase; Originally found in bacteria that live in hot springs; Does not denature at high temperatures used in PCR → can function in repeated cycles of heating and cooling

Gel Electrophoresis

A technique used for separating molecules based on their size (shape) and change

DNA profiling

Creates a fingerprint’ unique to an individual organism

Satellite DNA

Most genomes have short repeated DNA sequences

Restriction endonucleases

Chop satellite DNA into fragments that vary in length depending on number of repeats

Transcription

Temporary copies of DNA are made using mRNA which can leave the nucleus

Translation

mRNA is read by ribosomes which use the information to build specific amino acid sequences

Ribosomes

Composed of small subunit and large subunit; mRNA attaches to small subunit; tRNA attaches in large subunit (max 2 at a time); “Reads” mRNA to “translate” from the language of nucleotides to language of amino acids

tRNA (Transfer RNA)

Molecules: amino acid attached to one end, corresponding anticodon on the other end

Mutations

Changes to the DNA sequence; Can be harmful, neutral, or beneficial

Deletion

Removal of base(s)

Insertion

Addition of base(s)

Substitution

Replacement of base(s)

Single-nucleotide polymorphisms (SNPs)

Single base substitutions

Somatic cells

Normal body cells produced via mitosis (makes identical copies)

Germ cells

Reproductive cells (sperm and egg) produced via meiosis (makes haploid cells)

Meiosis

Nuclear division that produces four haploid nuclei from one diploid nucleus

Mitosis

Produces genetically identical diploid (2n) daughter cells; Occurs in somatic cells (normal body cells) to maintain and repair tissues

Crossing over

When equivalent portions of non-sister chromatids are exchanged between homologous chromosomes

Nondisjunction

During meiosis, sometimes gametes contain an extra or missing copy of a chromosome; Caused by failure of a pair of homologous chromosomes or sister chromatids to separate

Polar molecule

Polarity: partial charges on different parts of the molecule

Osmosis

Passive movement of water molecules from low solute concentration to high solute concentration (osmosis)

Toncity

Relative measurements comparing the concentrations of two solutions (must be put into context “in comparison to solution…”)

Hypertonic

Higher concentration of solute than the other solution

Isotonic

Same concentration of solute as the other solution

Hypotonic

Lower concentration of solute than the other solution

Gene

DNA sequence that codes for a protein

Allele

One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Genotype

The combination of alleles an organism has

Phenotype

In genetics, the phenotype is the set of observable characteristics or traits of an organism.

Homozygous

An organism with identical pairs of genes (or alleles) for a specific trait.

Heterozygous

A term that describes having two different versions of the same gene

Epigenetics

The study of how non-genetic factors can influence gene expression

Phenotypic plasticity

The capacity to develop traits suited to the environment experienced

Homeostasis

The maintenance of the internal environment of an organism, internal conditions maintained within narrow boundaries, despite external conditions

Negative feedback loop

Stimulus, Sensors, control sensor, effectors = effectors shut off stimulus by an organism by varying patterns of gene expression

Positive feedback loop

Stimulus, Sensors, Control center, effectors go to the stimulus; In positive feedback, the response makes the stimulus stronger → further away from homeostasis (eg. contractions during childbirth)

Thermoreceptors

Specialized nerve cells that detect differences in temperature

Insulin

Stimulates glucose uptake into muscles and liver cells; stored in glycogen;bloodsugar decreases

Glucagon

Stimulates glycogen hydrolysis, releases glucose from liver into blood; blood sugar increases

Stable ecosystem

Natural ecosystems are inherently stable and sustainable; They maintain their structure without additional nutrients or big changes in their composition; High biodiversity