PPT 8

Genetics

The study of traits and genes, focusing on how characteristics are inherited and passed down through generations.

Fredrick Griffith

Conducted an experiment in 1928 that showed the transformation of traits in bacteria, laying the groundwork for understanding DNA transfer.

EXPANDED ON GENETICS

Gregor Mendel

discovered genetics and traits related to genes 1866

Beadle & Tatum

In 1941, they proposed the "one gene, one enzyme" hypothesis, suggesting that genes direct the production of proteins.

Avery, McCarty, and MacLeod

Expanded Griffith's experiment in 1944, demonstrating that DNA, not protein, was responsible for genetic transformation.

Hershey & Chase

In 1952, they confirmed that DNA, not protein, is the genetic material in viruses.

Watson & Crick

Credited with discovering the double helix structure of DNA in 1953, with contributions from Rosalind Franklin.

McClintock

Discovered transposons in 1983, mobile genetic elements that can change their position in the genome. (cut paste mechanism)

Chargoffs rule

DNA from any cell of all organisms should have a 1:1 ratio (base pair rule)

Conjugation

The transfer of genetic material between bacterial cells through direct contact.

Name of the bridge that occurs btx bacteria during conjugation

PILUS

virtually al G-

not many G+

Transduction

The transfer of genetic material from one bacterium to another by a bacteriophage. ( virus )

Transformation

The process by which a cell takes up foreign genetic material from its surroundings. (exogenous) Natural & artificial, naked dna or plasmid dna and synthetic

Genome

The complete set of genetic information in an organism.

Gene

The functional unit of the genome, responsible for encoding proteins, RNA, or regulating gene expression.

3 functional unit of genome ( 3 types of genes )

structural

regulatory

RNA

Structural Gene

The most common type of gene that encodes proteins.

Genetics

The scientific study of genes, heredity, and genetic variation in living organisms.

Phenotype

The observable physical or biochemical characteristics of an organism.

Genotype

The genetic makeup of an organism, including all the genes and alleles.

Genetic Code

The universal code composed of four nucleotides (A, T, C, G, U) that specifies the amino acid sequence in proteins.

DNA Replication

The process by which DNA makes an identical copy of itself during cell division.

Transcription

The process of synthesizing RNA from a DNA template.

Translation

The process of synthesizing proteins from mRNA using tRNA and ribosomes.

central dogma

DNA unwinds> mRNA transcribed > trna > protein

Ribonucleic Acid (RNA)

A molecule similar to DNA but with ribose sugar and uracil instead of thymine.

Messenger RNA (mRNA)

Carries genetic information from DNA to the ribosome for protein synthesis.

Transfer RNA (tRNA)

Transfers specific amino acids to the ribosome during protein synthesis.

Ribosomal RNA (rRNA)

A component of the ribosome essential for protein synthesis.

codon

sequence of 3 nucleotides in mRNA that specifies a particular AA

anticodon

sequence of 3 nucleotides in tRNA that is complementary to a codon in mRNA

DNA Polymerase

Enzyme responsible for synthesizing new DNA strands during replication.

Helicase

Enzyme that unwinds the DNA double helix during replication. by breaking hydrogen bond

DNA gyrase

keeps it from / unwinding supercoil topoisomerase

SSB proteins

keeps strands of DNA seperated and prevent from coming back together

What do ribosomes do

make proteins

translation machines

binding sites on mRNA ( RBS) ribosome binding site

A - site, Arrival

P - site, peptide forming

E-site , arrival

travels 5’3 direction

3 stop codons

UAA, UAG, UGA

DNA ligase

on lagging strand, helps glue okazaki fragments

Okazaki Fragments

Short DNA fragments on the lagging strand synthesized discontinuously during replication.

Replication Fork

The point at which the DNA double helix unwinds during replication to create two replication forks.

what is the start codon

AUG on mRNA

RNA virus using what

REVERSE TRANSCRIPTASE rewrites RNA to DNA

Primase

synthesize short RNA squences called primers (primers = starting point for DNA synthesis) Starter.

Promoter

A region of DNA that initiates transcription of a particular gene.

Terminator

A sequence that signals the end of transcription.

Polysome

A complex of multiple ribosomes translating a single mRNA molecule simultaneously.

Initiation

The beginning stage of translation where the ribosome assembles on the mRNA.

Elongation

The stage of translation where amino acids are added to the growing polypeptide chain.

Termination

The final stage of translation where the ribosome reaches a stop codon and releases the polypeptide.

Post-Translational Modification

Process where polypeptides are modified after synthesis, often folded into specific 3-D structures with the help of protein chaperones, and modified for transport through the cytoplasmic membrane with a signal sequence.

Pre-mRNA

Precursor form of mRNA synthesized in eukaryotic transcription, which must be processed during and after transcription, including capping the 5' end with a methylated guanine derivative and polyadenylation of the 3' end.

Splicing

Process that removes introns (non-coding sequences) from mRNA, leaving only the exons (expressed sequences) for translation in eukaryotic cells.

Introns

non coding section of an RNA transcript or the DNA encoding it

Exons

used as the blueprints that will piece together AA and make PROTEINS

Signal Transduction

The transmission of information from outside the cell to the inside, allowing cells to monitor and react to external signals.

quorum sensing

allows cells to activate genes useful w critical mass

activate cells like, biofilm formation

sense density of their population

Two-Component Regulatory Systems

Regulatory systems in bacteria consisting of a

membrane-spanning sensor that responds to environmental variations by phosphorylating amino acids and a response regulator that turns genes on or off accordingly.

Antigenic variation

alteration of characteristics of surface proteins (antigens)

phase variation

switching genes on & off

ORF

open reading frame

dividing sequences of nucleotides in a NA

Operon

A set of regulated genes transcribed as a single mRNA along with its control sequences, such as the lac operon for lactose metabolism in bacteria.

Constitutive Enzymes

Enzymes synthesized constantly and play indispensable roles in central metabolism, like those involved in glycolysis.

Inducible Enzymes

Enzymes that are synthesized only when needed, avoiding the waste of resources, such as β-galactosidase in the presence of lactose.

DNA-Binding Proteins

Proteins that can act as repressors or activators in gene regulation, blocking or facilitating transcription by binding to specific DNA sequences.