Genetic Material & Structural Proteins Flashcards
Hereditary Material
Hereditary material of most organisms is contained in DNA molecules. DNA is responsible for directing protein synthesis. RNA controls intermediate steps involved in protein synthesis.
Genes
A sequence of DNA that is the basic unit of heredity. Are segments of DNA, which can code for proteins. Genes are located on larger structures called chromosomes. Offspring inherit traits encoded by genes present within their parents DNA.
Chromosomes
Genetic information is contained in structures called, Chromosomes. Chromosomes consist of tightly coiled DNA that winds around histone proteins. Winding process condenses DNA, allows for regulation of genes. Each specie has number of chromosomes. Ex: Eukaryotic (cells with nuclei) Humans have 46 chromosomes. Prokaryotic organisms like bacteria have a singular circular chromosome.
Function of Genes
A length of DNA that contains instruction to make a protein or regulate the making of proteins. Vary in size from a few hundred DNA bases to more than a million bases. Humans have 25,000 genes. Genes have structural and regulatory functions.
Structural genes
Converted into a short -lived RNA message (mRNA) that is decoded by the ribosomes and assembled into proteins that build structures of living things.
Regulatory genes
Control the expression of protein-coding genes by turning on or off activity, either directly or through a protein intermediate. Regulatory genes control the expression of different subsets of structural genes in different cell types. Not all cells will express the same genes. They will make different proteins. Ex: Skin cell will produce the protein Keratin. Other cell types wont make Keratin, therefore Regulatory genes will turn off genes that code for Keratin. Genes coding for needed proteins in a cell are “turned on” or expressed.
DNA I
Deoxyribonucleic Acid (DNA) is a macromolecule that contains genes that are coded instruction for a cell to produce proteins. Contains genetic information and is responsible for directing protein synthesis in living organisms. Twisted ladder made of phosphate and deoxyribose sugar molecules. Rungs of a ladder are composed of four nucleotide bases: Adenine-Thymine, Guanine-Cytosine.
Keratin
Protein made by epithelial keratinocytes.
Codon
Triplets of nucleotides that code for amino acids. A sequence of 3 nucleotides that codes for a specific amino acid or stop signal during protein synthesis. A gene for a specific protein can be thousands of codons long. Gene will end with a stop codon.
Nucleotides
Nucleotides are the monomers used to build DNA and RNA. Adenine-Thymine, Guanine-Cytosine, Uracil (replaces thymine).
Ribosomes
Organelles that assemble proteins. They assemble proteins from amino acids in the order specified by the codons of a gene.
DNA II
DNA molecule is composed of two strands (2 sides of the ladder). The two strands are complementary, means nucleotide bases of the 2 strands are paired correctly and specifically (A-T, G-C). between bases are linked by 2 hydrogen bonds between A-T and 3 hydrogen bonds between G-C. Bonds are strong because they are numerous. Can break so strands can allow DNA to replicate during transcription.
Transcription
The synthesis of RNA from a DNA template. Before a cell replicates chromosomes containing DNA must be copied t make 2 identical copies called chromatids. Chromatids are separated and 2 new cells will have copies of DNA.
Hydrogen Bonds
A type of non-covalent bond, a weak attraction between a hydrogen atom bound to an electronegative atom and a second highly electronegative atom. Complementary bases are linked by 2 hydrogen bonds (A-T), and 3 hydrogen bonds between (G-C). Hold complementary nucleotide bases together.
DNA III
Two strands of DNA run in opposite directions (anti-parallel). “Sense strand” is the DNA coded in the 5’ to 3’ direction. The “Anti-sense strand” is the other strand going in the 3’ to 5’ direction. The “Anti-sense strand” is used as a template in DNA replication and transcription.
Mutation
May arise during replication and is a permanent change in the nucleotide sequence of DNA. Occur by either substitution, deletion, or insertion of base pairs. Mostly non harmful, unless they lead to cell death or tumor formation.
RNA
Ribonucleic acid’s (RNA) principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins. Protein synthesis requires 3 types of RNA (messenger RNA (mRNA), transfer RNA (tRNA), ribosomal (rRNA). A single chain of ribose sugar-containing nucleotides. Nucleotides are [adenine-uracil ( uracil replaces thymine), guanine-cytosine]. Base pairing is A-U, G-C.
Transcription and Translation I
Protein synthesis can be described in 2 stages: transcription and translation. Transcription is the synthesis of RNA from a DNA template. Transcription = “to copy” “to rewrite” DNA is too big to leave nucleus there for it copies the code for a gene to mRNA.
Transcription and Translation II
RNA is smaller and can leave the nucleus and can carry information to the cytoplasm where protein synthesis takes place. mRNA is an exact copy of the template strand (5’ to 3’), except that thymine is replaced with uracil.
Translation and Transcription
Once mRNA has entered the cytoplasm through nuclear pores, rRNA in ribosomes attaches to mRNA strands and begins to “transcribe” the instructions. Each mRNA codon designates for a particular amino acid to be inserted into a protein peptide chain. The amino acids are “transferred” (tRNA) to the ribosome subunit and deliver the anticodon (codon) complement. tRNA releases the amino acid once the match is made. rRNA binds the match together via peptide bond. The result is a “protein.”
Translation
Protein synthesis that takes place after mRNA exits the nucleus and binds to a ribosome.
Template strand
A sequence of bases on a strand of DNA that is used to form a complementary mRNA molecule.
Peptide Bond
The link between amino acids in a protein.
DNA, RNA, GENES and CHROMOSOMES I
Human Genome has 23 pairs of chromosomes, for a total of 46 chromosomes. DNA is wrapped around a histone protein. Specific regions of the DNA molecule are called “genes.” Genes contain instructions for proteins or other regulatory molecules. RNA controls the steps of protein synthesis. Genes are made of that are 3 DNA nucleotide bases long. A gene can be thousands of codons long.
DNA, RNA, GENES, AND CHROMOSOMES II
Human chromosomes vary in length and each chromosome has a DNA molecule that has a specific number of genes. Ex; Eighth chromosome has DNA composed of billions of nucleotide bases. Genes on this chromosome code for proteins for brain development.
Genome
The complete set of genetic information in a cell.
