Genes & DNA

• Genes, located in cell nuclei, dictate heredity and daily bodily functions by controlling the synthesis of cellular structures, enzymes, and chemicals.
• Gene expression involves transcribing the genetic code in the nucleus to RNA, translating the RNA code, and forming proteins in the cell cytoplasm.
• The human body can form a large number of different cellular proteins because it has approximately 20,000 to 25,000 different genes that code for proteins in each cell.
• The quantity of different proteins produced by the various cell types in humans is estimated to be at least 100,000.
• Structural proteins, associated with lipids and carbohydrates, form intracellular organelles, while most proteins are enzymes catalyzing cell reactions.
• Enzymes facilitate oxidative reactions for cell energy and synthesize chemicals like lipids, glycogen, and adenosine triphosphate (ATP).

Building Blocks of DNA

• DNA comprises phosphoric acid, deoxyribose (a sugar), and four nitrogenous bases: adenine, guanine (purines), thymine, and cytosine (pyrimidines).
• Phosphoric acid and deoxyribose create the DNA molecule's helical strands, while the nitrogenous bases connect between strands.

Nucleotides

• DNA formation starts by combining one molecule of phosphoric acid, one of deoxyribose, and one of the four bases to form an acidic nucleotide.
• This process results in four separate nucleotides: deoxyadenylic, deoxythymidylic, deoxyguanylic, and deoxycytidylic acids, with one for each base.

Cell Nucleus Genes Control Protein Synthesis

• Genes are attached in large numbers end to end in the cell nucleus.
• Genes are in extremely long, double-stranded helical molecules of DNA.
• The molecular weights of DNA are measured in the billions.
• This DNA molecule consists of simple chemical compounds bound together in a regular pattern.
• Multiple nucleotides bind to form two DNA strands, connected by weak cross-linkages.
• Each DNA strand's backbone consists of alternating phosphoric acid and deoxyribose molecules.
• Purine and pyrimidine bases attach to deoxyribose molecules' sides, connected by loose hydrogen bonds between the bases.
• Adenine pairs with thymine, and guanine with cytosine.
• The hydrogen bonds are loose, allowing the strands to separate easily during cell function.
• Ten nucleotide pairs form each full turn of the DNA helix.

Genetic Code

• The code lies when the DNA molecule splits apart.
• The code is purine and pyrimidine bases projecting to the side of each DNA strand.
• The genetic code consists of successive triplets of bases or sets of three, which form a code word.
• Triplets dictate the sequence of amino acids in synthesized proteins. Each triplet is responsible for the successive placement of three amino acids
• The example shows proline, serine, and glutamic acid, in a newly formed protein molecule.

Transcription

• DNA genes in the nucleus control cytoplasm's chemical reactions, where most cell functions occur.
• RNA, controlled by DNA, mediates this control.
• The code transfers to RNA: A process called transcription.
• RNA then diffuses through nuclear pores into the cytoplasm to control protein synthesis.
• During RNA synthesis, DNA strands separate temporarily, using one strand as a template.
• DNA’s code triplets form complementary code triplets, or codons, in RNA, which then control the amino acid sequence in proteins synthesized in the cell cytoplasm.
• Basic building blocks of RNA mirrors the construction of DNA, but with two exceptions.
• Deoxyribose gets swapped out for ribose (which contains an extra hydroxyl ion appended to the ribose ring structure)
• Thymine gets swapped out for uracil (a pyrimidine)
• The four separate nucleotides containing adenine, guanine, cytosine, and uracil form RNA.
• Uracil replaces thymine in RNA.

Activation of RNA Nucleotides

• RNA polymerase activates RNA nucleotides by adding two extra phosphate radicals to each nucleotide. This forms triphosphates, combining with the nucleotide via high-energy phosphate bonds from ATP, yielding large quantities of ATP energy for each nucleotide. This is the " Activation" of RNA nucleotides.
• Energy then promotes chemical reactions, adding new RNA nucleotides at the end of the developing RNA chain.

Assembly of RNA

• RNA assembles due to RNA polymerase: A large protein enzyme with properties necessary for RNA formation
• In the DNA strand, the nucleotide sequence promoter exists just ahead of the gene to be transcribed.
• RNA polymerase recognizes and attaches to this promoter because of the RNA polymerase having an appropriate complimentary structure , initiating RNA synthesis.

RNA Polymerase

• After the polymerase's attachment, it unwinds about two turns of the DNA helix, separating the unwound portions.
• The polymerase moves along the DNA strand & unwinds/separates in stages. It hydrogen bonds the end base of the DNA strand with an RNA nucleotide in the nucleoplasm.
• Then, it breaks two of the three phosphate radicals away from each RNA nucleotide.
• Liberated energy from broken high-energy phosphate bonds lead to covalent linkage of the remaining phosphate on the nucleotide with the ribose on the end of the growing RNA chain.
• Chain-terminating sequence halts polymerase once it reaches the end of the DNA gene, breaking away the polymerase and RNA chain and making the polymerase reusable for forming chains.
• New RNA strand’s weak bonds with the DNA template break with the DNA rebonding with DNA via high affinity, thus forcing the RNA chain away to release into the nucleoplasm.
• The code from the DNA strand eventually transmits complementarily to the RNA chain.

RNA Bases

• RNA base guanine combines with DNA base cytosine
• RNA base cytosine combines with DNA base guanine
• RNA base uracil combines with DNA base adenine
• RNA base adenine combines with DNA base thymine

Different Types of RNA

• Some RNAs involve in protein synthesis. Other RNA types regulate genes or participate in RNA's post transcriptional modification.
• RNA types with unknown roles are considered mysterious, including several which don't seem to code for proteins.

Six Types of RNA

• Precursor messenger RNA (pre-mRNA) gets processed to forms mature messenger RNA (mRNA). This occurs when introns are removed by splicing and exons are retained in the final mRNA.
• Small nuclear RNA (snRNA) leads the splicing of pre-mRNA to form mRNA.
• Messenger RNA (mRNA) delivers the genetic code to the cytoplasm to regulate protein formation.
• Transfer RNA (tRNA) brings activated amino acids to the ribosome to be the building blocks of the protein molecule.
• Ribosomal RNA along plus different approximately 75 proteins forms ribosomes, the physical and chemical sites of assembled protein molecules.
• MicroRNAs (miRNAs) are single-stranded RNA molecules of 21-23 nucleotides which can regulate gene transcription and translation.

Messenger RNA (mRNA)

• Messenger RNA molecules are long single RNA strands suspended in the cytoplasm with unpaired strands contain codons for DNA genes.

RNA Codons

• Several amino acids are represented by more than one codon.
• One codon represents “start manufacturing the protein molecule."
• Three codons represent “stop manufacturing the protein molecule."

Transfer RNA (tRNA)

• Transfer RNA (tRNA) transfers amino acids to protein molecules while they're being synthesized
• Each tRNA type combines specifically with 1 of the 20 amino acids to be incorporated into proteins.
• Then tRNA transports its amino acid to the ribosome.
• Each tRNA recognizes an mRNA codon: Delivering the amino acid into its place along the chain.
• tRNA contains around 80 nucleotides for each molecule.
• One end of the molecule always contains adenylic acid, which attracts amino acids to connect at a hydroxyl group on the ribose.
• Each tRNA type must have certain specificity for a specific codon in the mRNA.
• Anticodon: A triplet of nucleotide bases - specificity is gained from this code in the tRNA which makes recognizing a codon.
• The anticodon is located in the center of the tRNA molecule.
• The anticodon bases combine through hydrogen bonding with the mRNAs codon bases to line up along a chain, creating protein molecules.

Ribosomal RNA (rRNA)

• Ribosomal RNA (rRNA) comprises about 60% of the ribosome, while proteins make up the remainder
• The ribosome associates with the two other RNAs.
• tRNA transports amino acids to ribosomes to incorporate them into the developing protein.
• The ribosome contains large amounts of ribosomal RNA due to requiring large functionality for cell function.
• mRNA provides information for each protein type.
• Ribosomes can't form in the cell nucleus.
• The ribosome acts as a manufacturing plant in which the protein molecules are formed.

Formation of Ribosomes in the Nucleolus

• DNA genes create ribosomal RNA in five pairs of chromosomes in the nucleus.
• Each chromosome contains duplicates of these genes because of the large amounts of ribosomal RNA required for cellular function.
• The forming ribosomal RNA collects in the nucleolus (a structure adjacent to the chromosomes) and then binds with ribosomal proteins to form primordial subunits of ribosomes.
• Large amounts of ribosomal RNA synthesizes in cells that manufacture large amounts of protein.
• These subunits releases from the nucleous and move via nuclear pores into the cytoplasm where they assemble mature functional ribosomes.

MicroRNA (miRNA) molecules:

• Processed by the cell into molecules complementary to mRNA.
• They act to decrease gene expression.

Small Interfering RNA (siRNA) molecules:

• Short, double-stranded RNA fragments that interfere with expression of specific genes.
• Commonly used in research.
• Tailored for a sequence in the gene.
• Can block translation of an mRNA & therefore expression by any gene for which the nucleotide sequence is known.

Translation

• Translation is initiated by the mRNA and ribosome coming into contact, the ribosome has an appropriate sequence of RNA bases for a chain.
• Then a protein molecule has the process of translation.

Messenger RNA

• The ribosomes is responsible for reading each of the codons in the same way a tape passes through the playback head.
• When the “stop” codon is reached, the process will slip past the ribosome, which stops the creation of a protein molecule as it is freed into the Cytoplasm.

Polyribosomes

• A sole mRNA molecule produces protein molecules in several ribosomes concurrently.
• Cluster: Multiple ribosomes are attached single mRNA.

Ribsomes

• Ribosomes form a protein molecule.
• Are able to connect the endoplasmic reticulum with the specific receptor sites on the endoplasmic reticulum, this causes the molecule to enter the lumen and reticulum walls.

Protein Synthesis Steps:

• Each amino acid needs to be activated by a process or in combination with ATP to form adenosine.
• The Amino acid activates energy and then combines or uses the TRNA.
• TRNA with acid reaches MRNA and connect or touch ribosomes allowing for the TRNA to connect allowing molecules to be the right protein.

Peptide Linkage

• This occurs when the amino acids combine with one another creating this action:

Enzyme Synthesis

• 1,000 of protein enzymes that formed regulate most of the chemical reactions in the cells.
• Enzymes encourage lipids ,glycogen ,pyramiding and many substances.

Gene Control

• Genes control the operations of cells.
• Gene functions must also be controlled: otherwise, some parts of the cell might overgrow or some chemical reactions might overact

Control Methods

• Genetic regulation: the activation from genes to forming products is control.
• Enzyme Regulation: The activities or levels of enzymes under control

Genetic Regulation

• Genetic regulation expression blankets almost everything from genetic coding to creation of protein.
• Gene expression Provides organisms abilities to change the environment.

Promoter: Gene Expression

• Process for forming proteins for a cell, needs transcribing with its MRNA or RNA.
• Eukaryotes Promoter includes TATA, binding proteins which include factors IID
• Transcription factor -IIB Binds to the DNA or polymerase 2 Facilitation.
• Upstream promoter - it is further from the start site for transcriptions for regulators and negative regulatory effects.

Control For Transcription

• Located from the genome.
• Regulatory proteins helps as a activator and repressor.
• controlled on the DNA strand
• DNA into specific units the chromosomes

Enzyme

• Activities of some enzymes that are active enzymes

Enzyme Inhibitions

• Feedback effects of the enzyme systems from the cell.
• Most product acts -as an allosteric conformation.

Control. Systems

• feedback monitors cell structures to makes changes by making corrections
• Activations controls inside the sell

Cell Reproduction

• Another example of the genetic system and cells can be developed by a single cell.
• Life cycle: the period for cell production , reproduction when all the cells product more
• Mitosis: a event when it happens, has well events to split cells.
• Interphase: the period between mitosis

DNA

• Occurs before Mitosis taking Place or duplication with taking DNA.
• It occurs after the process

Processes

• Strands of DNA- it is duplicated not that same amount as the one they are transcribed
• Polymerase- comparable replicates, nucleotides which connects after an enzyme
• Replication- It happens at the end.
• Primmer binding- Short time pieces of the RNA and the strans.
• Elongation- Enzymes with new ways and directions can increase the pressure.

Telomere

• It protects the caps and chromosomes that don’t allow any deterioration through cells.
• Occurs for divisions shorts piecing of primers during cell division the copy is lacking due to cells.

Regulation cell size

• almost cell sized is cause function of the DNA AND THE It’s all by the ammount

Dna regulation

• It can be a variety in which changes due phsycal with the cell body's structure.
• Well-defined and frog body

Apoptosis- death.

• Communities and bodies are not only regulates by dividing also cell death
• Causes The cell shrinks, disassembling the surface that is being held ,or broken.

Apoptosis vs Necrosis

• Is programmed cell death.
• Cells swells the membrane loses integrity, a injury in a regular cell.

Activations

• Family of activators that synthesized and store for casing of active breaks

Cancer

Caused by mutations and cell. And cell mitosis can increase the ability of the cells Proto / genes that cell the cell growths and divisions that also effects the gene

Causes of Cancer

• Caused by DNA , strand which replictated with the procces
• Radiation a ability of cells to strand.
• Chemicals types- also causes cell, or mutations from tobacco or smokes

Invasives Characteristics

• They don’t not require the factors for the growth.
• Less that are cell. and those travel threw tissue.
• The also produce factors.and the require cancer.

Dna Killers

• Cancer cells are continue to increase and the cells nutrient death
• Those cell Disrupt body.

Explore genes, expression, and DNA structure. Understand how genes control cell function through protein synthesis. Learn about nitrogenous bases and the impact of mutations.