DNA Replication, Transcription, and Translation

Flashcards covering key concepts in DNA replication, transcription, and translation based on lecture notes.

Goal of DNA Replication

Copy the entire DNA before cell division.

Where DNA Replication Occurs

Nucleus (in eukaryotes)

Helicase

Unzips double helix by breaking hydrogen bonds during DNA replication.

Single-Strand Binding Proteins (SSBs)

Stabilize separated strands during DNA replication.

Topoisomerase

Prevents supercoiling ahead of replication fork during DNA replication.

Primase

Adds short RNA primers to provide 3'-OH end during DNA replication.

DNA Polymerase III

Synthesizes new DNA (5'→3') from primer during DNA replication.

DNA Polymerase I

Replaces RNA primers with DNA during DNA replication.

Ligase

Joins Okazaki fragments to form a continuous strand during DNA replication.

Goal of Transcription

Make mRNA from a gene to carry instructions.

Where Transcription Occurs

Nucleus (in eukaryotes)

Promoter region (TATA box)

Signals start of transcription; where RNA Polymerase II binds with help of transcription factors.

RNA Polymerase II

Reads DNA (template strand) and synthesizes pre-mRNA (5'→3').

RNA Processing (Eukaryotes only)

5' cap and 3' Poly-A tail added; introns removed, exons joined.

Goal of Translation

Build protein using mRNA instructions.

Where Translation Occurs

Cytoplasm (at ribosomes)

mRNA

Carries code for translation.

tRNA

Delivers amino acids for translation.

Ribosome (rRNA + proteins)

Reads codons and links amino acids during translation.

Initiation of Translation

tRNA with anticodon (UAC) brings Methionine (AUG = start codon).

Elongation of Translation

Ribosome reads mRNA codon by codon; tRNA brings correct amino acid; peptide bonds form.

Termination of Translation

Stop codon (UAA, UAG, UGA) is reached; release factor releases polypeptide.

Function of Topoisomerase

Relieves tension ahead of replication fork

Function of RNA Polymerase II

Makes mRNA

Function of Ribosome

Builds protein

Replication

Copy DNA

Transcription

DNA ➔ mRNA

Translation

mRNA ➔ Protein

Reverse transcription

Process by which RNA molecules are reverse transcribed into complementary DNA (cDNA).

Translation

A process of protein synthesis, where the RNA information is expressed as polypeptide chains.

Regulation

Translation is regulated by the interaction of ribosomal units with the transcription complex.

End product of Transcription

Includes mRNA, tRNA, rRNA, and non-coding RNA.

Transcription

The process of synthesizing an RNA molecule from a DNA template

Translation

The process of decoding the mRNA sequence and synthesizing a protein

prokaryotic

organism where cells lack a nucleus and other organelles

eukaryotic cell

possesses nucleus, cell have membrane bound nucleus

nucleus

the structure in a cell that contains chromosomes

mitochondria

power house of the cell, generating ATP through cellular respiration.

chloroplast

tendency of an atom to attract electrons in a molecule due to specific atomic structure each element will have a different tendency to hold to some of its outermost electron

protonated

atom, molecule or ion has added a hydrogen ion (H+) becoming a conjugate acid

de-protonated

lost a hydrogen ion becoming conjugate base

condensation

bond formation with loss of water

hydrolysis

bond breakage with addition of water

electronegativity

tendency for an atom to attract shared electrons when formin a chemical bond or an atom ability to complete for electrons with other atoms bonded.

lipids

store and gather energy (fat to burn photosynthetic pigment)

prions

infectious proteins that cause misfolding of other proteins, leading to neurological diseases.

ATP synthase

an enzyme that catalyzes the formation of ATP from ADP and inorganic phosphate during cellular respiration.

allosteric regulation

the modulation of an enzyme's activity through the binding of an effector molecule at a site other than the active site, affecting its function.

amino acid

organic compounds that serve as the building blocks of proteins, consisting of an amino group, a carboxyl group, and a unique side chain. H2N

peptide bond

a covalent bond formed between two amino acids during protein synthesis, linking the carboxyl group of one amino acid to the amino group of another.

potential energy

used to do work including reduction of energy in a system due to its position or state, such as stored energy in chemical bonds.

entropy

a measure of system thermal energy per unit temperature that is unavailable for for using useful work

catalyst

a substance that speed up reaction without participating in it either reactant or a product.

Glycolysis

a metabolic pathway that converts glucose into pyruvate, a process that occurs in the cytoplasm of all cells and does not require oxygen. It's the first stage of cellular respiration and a crucial energy-producing pathway for both aerobic and anaerobic organismss

fermentation

recycling NADH back to NAD+ in the absence of an external electron acceptor

TCA cycle

complete oxidation of glucose

glycolysis input and outputs

Inputs: glucose, ATP, NAD+; Outputs: pyruvate, NADH,

diffusion

high to low concentration , movement due to kinetic energy

active transport

calso via membrane protien but low to high concentrations

eurkaryotic cell

all mitochondria, cytoplasm and nucleus

ATP SYSTASE

membrane synthases with ATP in mitochondria inner membrane main energy currency from protein gradient