Biology Module 3 Overview - DNA & Genetics

bsc 1005

Nucleus

Cell's control center containing DNA in chromosomes.

Chromosomes

DNA + proteins, control protein production.

Nuclear Envelope

Double membrane around nucleus; regulates passage in/out.

Nuclear Pores

Openings in the nuclear envelope; allow materials like RNA to pass.

Nucleolus

Ribosome production site.

Chromatin

DNA-protein complex, uncondensed in interphase, condensed during cell division.

DNA

Genetic material, stores information in sequences of nucleotides.

Nucleotide

DNA unit with three parts—deoxyribose sugar, phosphate group, nitrogen base.

Nitrogen Bases

Adenine (A), Guanine (G), Cytosine (C), Thymine (T).

Double Helix

DNA structure, two strands twisted around each other.

Base Pairing

A pairs with T, C pairs with G.

Backbone

Sugar-phosphate structure holding DNA together.

Purpose of DNA Replication

Creates exact copies of DNA for cell division.

Semi-Conservative

Each new DNA has one old and one new strand.

Process of DNA Replication

DNA strands separate; each serves as a template for new strands.

DNA Synthesizer

Machine to create specific DNA sequences (e.g., primers).

PCR (Polymerase Chain Reaction)

Technique to amplify specific DNA segments.

Thermal Cycler

Device used in PCR to heat/cool DNA for replication.

Purpose of Gel Electrophoresis

Separates DNA fragments by size.

Process of Gel Electrophoresis

DNA moves through gel with electric current; small fragments move faster.

Result of Gel Electrophoresis

Visible DNA bands for analysis.

STRs

Repeated DNA sequences unique to individuals.

Application of STRs

Identify individuals by comparing STR patterns at 13 specific sites.

Method of DNA Profile Analysis

Uses PCR and gel electrophoresis on STR sites to create DNA profiles.

Uses of DNA Profile Analysis

Crime scene ID, paternity tests, identifying remains, ancestry analysis.

CODIS

U.S. DNA database with profiles from offenders and forensic samples.

Use of CODIS

Matches DNA profiles for criminal investigations and serial crime links.

Eukaryotic nucleus

Membrane-bound organelle containing cell's genetic material.

Nuclear envelope

Double membrane surrounding the nucleus.

Nuclear pores

Openings allowing molecule passage between nucleus and cytoplasm.

Nucleolus

Dense region where ribosomes are assembled.

Chromosomes

Thread-like structures carrying genetic information.

Histones

Proteins around which DNA is tightly coiled.

Chromatin

Complex of DNA and proteins in non-dividing cells.

Centromere

Constricted region for spindle fiber attachment.

Mendelian inheritance

Inheritance patterns established by Gregor Mendel.

Dominant allele

Allele determining phenotype in a single copy.

Recessive allele

Allele determining phenotype only in two copies.

Law of segregation

Alleles separate during gamete formation.

Incomplete dominance

Heterozygote exhibits intermediate phenotype.

Codominance

Both alleles expressed equally in heterozygote.

Polygenic inheritance

Multiple genes contribute to a single trait.

Sex-linked inheritance

Inheritance of genes on sex chromosomes.

X-linked traits

Traits controlled by genes on the X chromosome.

Punnett square

Diagram predicting offspring genotypes and phenotypes.

Pedigree

Diagram tracking trait inheritance across generations.

Transcription

Process of copying DNA sequence into mRNA.

Translation

Assembly of amino acids based on mRNA codons.

RNA polymerase

Enzyme catalyzing mRNA synthesis during transcription.

Codons

Triplets of nucleotides specifying amino acids.

Hemophilia

X-linked recessive disorder causing bleeding issues.

Mitosis

Cell division ensuring equal DNA distribution.

Meiosis

Cell division producing gametes with half DNA.

Transfer RNA (tRNA)

Molecules that transport amino acids to ribosomes.

Polypeptide

Chain of amino acids forming a protein.

Mutation

Change in DNA sequence affecting genetic information.

Point Mutation

Change in a single nucleotide within a gene.

Silent Mutation

Mutation that does not alter amino acid sequence.

Missense Mutation

Mutation that changes one amino acid in sequence.

Nonsense Mutation

Mutation introducing a premature stop codon.

Frameshift Mutation

Insertion or deletion altering gene reading frame.

Single-gene Disorder

Genetic disease caused by mutation in one gene.

Chromosomal Disorder

Abnormalities in chromosome number or structure.

Multifactorial Disorder

Disease from genetic and environmental factor interactions.

Mitochondrial Disorder

Disorder caused by mutations in mitochondrial DNA.

Physical Examination

Assessment revealing characteristic features of disorders.

Family History

Analysis of inherited patterns for genetic risk.

Genetic Testing

DNA analysis to identify specific mutations.

Prenatal Testing

Screening during pregnancy for genetic disorder risks.

Whole-genome Shotgun Method

Technique for sequencing entire genomes using fragments.

DNA Profiling

Identifying individuals based on unique DNA sequences.

Gene Therapy

Treatment aiming to correct genetic disorders.

Retrovirus

Virus used as a vector in gene therapy.

Cell Theory

All living organisms are composed of cells.

Cell Division

Process producing two daughter cells from one.

Sexual Reproduction

Fusion of gametes to form a zygote.

Fertilization

Sperm and egg fusion forming a zygote.

Zygote

Diploid cell from sperm and egg fusion.

Asexual Reproduction

Reproduction without gamete fusion, offspring are identical.

Gametes

Haploid cells involved in sexual reproduction.

Life Cycle

Sequence of reproductive stages from conception onward.

Diploid (2n)

Cell with two sets of chromosomes, 46 in humans.

Haploid (n)

Cell with one set of chromosomes, 23 in gametes.

Somatic Cells

Body cells excluding reproductive cells.

Gonads

Organs producing gametes; testes in males, ovaries in females.

Karyotype

Visual representation of chromosomes in homologous pairs.

Homologous Chromosomes

Chromosome pairs with same traits from each parent.

Sex Chromosomes

Chromosomes determining an individual's sex (X, Y).

Cytokinesis

Division of cytoplasm at end of cell division.

Independent Assortment

Random distribution of chromosomes during meiosis I.

Random Fertilization

Any sperm can fuse with any egg.

Crossing Over

Exchange of genetic material between homologous chromosomes.

Nondisjunction

Failure of chromosomes to separate properly during meiosis.

Trisomy 21

Disorder with three copies of chromosome 21.

Down Syndrome

Genetic disorder caused by trisomy 21.

Reproductive Systems

Organ systems for gamete production and delivery.

Spermatogenesis

Process of sperm production in the testes.

Prostate Gland

Secretes fluid contributing to semen in males.

Urethra

Tube carrying urine and semen in males.

Vas Deferens

Duct transporting sperm from epididymis to urethra.