BIO 105 THIRD EXAM
Terms in this set (93)
universal information-storage molecule found in the cells of every living organism along with some viruses.
Encodes the instructions for building all of a cell's proteins along with regulatory sequences for determining when and where each protein is expressed.
Double helix structure
Encodes and stores an enormous amount of information in a compact space;
Complementary strands help prevent mutations or correct errors when they occur; and
Provides accurate templates for rapid DNA replication.
Four nitrogenous bases
Purines: Adenine (A), Guanine (G)
Pyrimidines: Cytosine (C), Thymine (T)
Two complementary strands of DNA double helix running in opposite directions
The 5' to 3' direction
DNA can only be synthesized in:
Two identical helices, each with one "old" strand and one "new" strand.
The building block of DNA and RNA
A linear polymer strand of DNA or RNA
Two antiparallel strands of DNA
DNA associated with an array of different proteins into a complex structure.
Entire chromatin strand
The complete complement of genetic material in an organism
Origins of replication
Localized unwinding's where DNA replication is initiated
Protein associated with the unwinding of the DNA helix
Single strand binding proteins
Single stranded unwound regions are stabilized
The helix ahead of the replication fork is stabilized
Short complementary sequences of RNA (primers) are laid down to initiate synthesis
DNA polymerase III
DNA nucleotide's are added one by one starting from the RNA primers.
DNA polymerase I
RNA primers are later removed and replaced with DNA nucleotides.
Any gaps between nucleotides are joined to yield continuous strands.
A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.
Travels along one DNA strand in the 5' to 3' direction and separates the strands
DNA synthesized as one long molecule.
DNA primase makes a single RNA primer.
DNA polymerase adds nucleotides in a 5' to 3' direction as it slides forward behind the replication fork
DNA still synthesized 5' to 3' but in short chunks (Okazaki fragments).
A new primer must be laid down for each fragment as the replication fork opens.
Short newly synthesized DNA fragments that are formed on the lagging template strand during DNA replication.
Production of a transcript (RNA copy) of a gene from the genome.
Transcript is generally a messenger RNA (mRNA) that specifies the amino acid sequence of a polypeptide.
Process by which a ribosome synthesizes a specific polypeptide using an mRNA template.
Gene coding region aka transcribed region
Provides the instructions for forming the functional product.
Stretches of DNA that are important for controlling when the gene is transcribed
Is the process of copying a gene into a complementary mRNA strand
RNA polymerase II
Transcribes mRNAs from protein-coding genes.
RNA polymerase I and III
Transcribes nonstructural genes into ncRNAs like rRNAs and tRNAs.
A transcription factor (sigma factor) binds to a gene's promotor and directs RNA polymerase to bind, ends when DNA strands open.
RNA polymerase slides along DNA and synthesizes a complementary mRNA in the 5' → 3' direction from the template strand of DNA.
RNA polymerase reaches the terminator sequence and releases from the DNA
Protein-coding genes include t regions that are transcribed and translated
Regions that are transcribed but not translated
Introns must be removed from pre-mRNAs before translation
Complexes of small nuclear RNAs and proteins
Splicing can occur more than one way to produce different products Splicing can occur more than one way to produce different products
During translation, mRNAs are read in blocks of three bases each. Each possible codon codes for a particular amino acid and/or the start or stop position for protein synthesis.
More than one codon can specify the same amino acid.
Transfer RNAs (tRNAs)
Are the adaptors that carry the appropriate amino acids to the ribosome during translation.
Refers to the ability of cells to control their level of gene expression
Some genes code for products needed for basic life functions
Transport oxygen through the bloodstream
Proteins are modified after translation
Are specific transcription factors that bind to enhancers and increase gene expression
Are specific transcription factors that bind to silencers and decrease gene expression
Specific transcription factors can bind and either increase or decrease expression of the gene
Changes to the DNA sequence of a cell's genome
Direct DNA damage from environmental agents. (chemicals, high energy radiation e.g. UV light, radioactive substances)
Copying errors that are repaired during DNA synthesis
The sequence of DNA base pairs is changed.
One or more base pairs is added to or removed from the DNA.
If only a single base pair is affected, the substitution/addition/deletion
Does not alter the amino acid sequence of the protein coded for by the gene
Alters one amino acid but leaves the majority of the protein sequence unchanged
Introduces an incorrect stop codon that shortens the protein (a nonstop mutation does the reverse and converts a stop codon to a normal codon)
Results from the addition or deletion of base pairs in multiples other than three, altering the polypeptide sequence at all points after the mutation
All non-reproductive cells
sperm and eggs
Can be passed on to offspring via sexual reproduction
Somatic cell mutations
Cannot be passed on to offspring, but are passed on to daughter cells via mitosis.
Disease of multi-cellular organisms characterized by uncontrolled cell division
Is an overgrowth of cells in a tissue caused by some problem in the regulatory pathways that control cell division
Benign aka pre-cancerous growths
Do not invade other tissues or spread far throughout the body.
Have lost all normal regulation of cell division and growth.
These cells can invade healthy tissues and can migrate to distant parts of the body (metastasis).
Genes that can cause cancer
After the gene has mutated and become overactive
Branch of biology that studies how genes influence traits of organisms and how genes are inherited across generations
Acquisition of traits by offspring from their parents
The chromosomal regions where genes are located
Singular Chromosomal region
Different gene variants that individuals have at each locus
The genetic makeup of an individual or cell
The outward physical and behavioral characteristics of an organism, which can be affected by its genotype.
Different aspects of an organisms phenotype
Masks the phenotypic effects of the other allele, which is referred to as recessive.
Two copies of the same allele
Two different alleles at a locus
Mendel experimentally bred peas from different strains together and followed what happened to the single trait he was interested in over subsequent generations
Mendel's law of segregation
Mendel inferred that each pea plant has two alleles for each trait, and that the alleles segregate from each other during gamete formation such that each gamete contains only one allele
Adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length, that serves as the physical link between the mRNA and the amino acid sequence of proteins
Large family of RNA molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression
Single strand binding proteins
These proteins are important for stabilizing unwound DNA at a replication fork and preventing the two strands from coming back together:
During DNA synthesis, the lagging strand is synthesized in a discontinuous way. The short fragments of the lagging strand that are eventually joined together at the end of DNA replication are called:
Modification of chromatin structure
Loosening up of the chromatin in the region where a gene is located, making it easier for RNA polymerase to transcribe the gene.
If a molecule regulates the process of transcription
Usually inhibits transcription, either by blocking an activator protein or by recruiting proteins that inhibit transcription.
Closed (condensed) chromatin
DNA is not accessible to TFs or RNA polymerase, transcription cannot occur
DNA is accessible to TFs and RNA polymerase, transcription can occur
Some genetic mutations decrease or knock out an important cellular component/process