BIOL 330 Exam 1 Lectures 1-3

What are the four characteristics that the genetic material must exhibit?

• replication

• mutation

• information storage

• expression of traits

Until 1944, observations believed what was genetic material?

Proteins

Why does RNA serve as the genetic material in some viruses?

Because it can store genetic information and is capable of replication, allowing viruses to reproduce

How did Mendel discover the basic principles of heredity?

Through pea plant experiments, Mendel observed inheritance patterns, leading to his formulation of the laws of segregation and independent assortment.

What is character?

A heritable trait that varies among individuals, such as flower color or seed shape in plants.

What is a trait?

A specific characteristic or feature of an organism that can be inherited, such as eye color or height.

• an obvious, observable, measurable, physical or biochemical characteristic of an organism

What is a trait called?

The expression of genes in an observable way

What is a genotype?

The genetic makeup of an organism, consisting of its specific set of genes

What is genetics defined as?

The branch of biology concerned with the study of heredity and variation

• the study of the origin, transmission, and expression of genetic information

What is inheritance or heredity?

The transmission of traits from one generation to the next

Along with inherited similarity, there is?

Variation

What are the divisions of genetics?

• Transmission genetics

• Molecular genetics

• Population genetics

What is transmission genetics?

• The basic principles of heredity

• How traits are passed from one generation to the next

• Focus is on the individual organism

What is molecular genetics?

• The chemical nature of the gene

• How genetic information is encoded, replicated, and expressed

• Focus is the gene and its structure, organization, and function

What is population genetics?

• The genetic composition of populations

• How genetic composition changes geographically and with the passage of time

• Focus is the group of genes found in a population

Inheritance is governed by information stored in discrete unit factors (the fundamental, physical, functional unit of heredity) called?

Genes

A DNA sequence coding for a single polypeptide or an RNA molecule is?

a gene

To serve as genetic material, molecule must be able to?

• Replicate (faithfully)

• Store information (contain complex information)

• Express information (encode phenotypes)

• Allow variation by mutation (have the capacity to vary)

Division is made up of?

Cells + genetic material

Mitosis makes? Meiosis makes?

Somatic cells

Germ/sex cells (gametes)

To serve as genetic material, a molecule must be able to express information - which means?

They should be able to express their RNA or protein

What is central dogma? (will be on exam)

The classical concept of the flow of genetic information from DNA to RNA and then to protein, illustrating how genes are expressed

DNA makes ____ (transcription), which makes ___ (translation)

DNA makes RNA (transcription), which makes proteins (translation)

What are the exceptions to central dogma?

• Reverse transcription (RNA → DNA)

• RNA replication (RNA → RNA) in some RNA virus

• Non-coding RNAs that function without being made into proteins

What is a mutation?

A change in the nucleotide sequence of DNA

Mutations do what?

Introduce new alleles to the population in which natural selection operates

The central dogma specifies that the information in DNA is?

Copies into an RNA molecule during transcription, and the information in that RNA molecule is used to make a protein during translation

What is the chromosome theory of inheritance?

The chromosome theory of inheritance states that genes are located on chromosomes, and that the behavior of chromosomes during meiosis and fertilization is the basis for the inheritance of traits

Chromosomes are the carriers of?

Genetic material

Drosophila melanogaster is?

A common species of fruit fly commonly used in genetic research

What characteristics make fruit flies a convenient organism for genetic studies?

• They produce many offspring

• A generation can be bred every two weeks

• They have only four pairs of chromosomes

• Large number of mutants allow for construction of extensive chromosome mapping

What are mutant phenotypes?

Variations in observable traits that differ from the wild type, often caused by mutations in specific genes

What is the difference between wild type (or normal) type of phenotypes?

The wild type refers to the most common phenotype or genetic makeup in a population

Why did geneticists in the 1940s favor protein?

Because proteins were diverse and abundant in cells

DNA stands for?

Deoxyribonucleic acid

DNA is?

A polymer of nucleotides, each consisting of a nitrogenous base, a sugar, and a phosphate group

The nitrogenous bases in DNA can be?

Adenine (A), thymine (T), guanine (G), or cytosine (C)

The nitrogenous bases store?

Genetic information and code for proteins

What is protein?

Amino acids that are linked together by peptide bonds (polypeptides)

How does a covalent peptide bond form?

Forms when the carbon atom of the carboxyl group of one amino acid shared electrons with the nitrogen atom from the amino group of a second amino acid

What classifies peptide bond formation as a condensation reaction?

When water is released during the formation of the bond between amino acids

The sequence of chemically distinct side chains gives each protein its distinct?

structure and function

The general formula of an amino acid is?

• Amino group NH2

• a- Carbon atom

• Carboxyl group COOH

• R side chain

The role of DNA in hereditary was first discovered by?

Studying bacteria and viruses that infect them

Polysaccharide capsules differ from nonencapsulated bacteria how?

Polysaccharide capsules have a thick polysaccharide capsule on their surface and it helps the strain able to protect itself.

Nonencapsulated bacteria are not able to protect itself, they are engulfed and destroyed by phagocytic cells

Transforming substance/principle theory is?

The theory that DNA is the substance responsible for transferring genetic information, demonstrating that DNA can transform the characteristics of an organism.

What molecule serves as the transforming principle?

DNA

What does protease do?

Catalyzes the hydrolysis (breakdown) of peptide bonds in proteins

What does ribonuclease (RNAse) do?

Catalyzes the degradation of RNA by hydrolyzing its phosphodiester bonds

What does deoxyribonuclease (DNAse) do?

Catalyzes the degradation of DNA by hydrolyzing its phosphodiester bonds

Transformation is ____ and the process affects the ____ ____

Transformation is hereditable and the process affects the genetic material

What is a virus (phage)?

A small collection of genetic code, either DNA or RNA, surrounded by a protein coat

Viruses that attach themselves to bacteria, empty their genetic material into them, and lead to the rapid spawning of new phage inside the bacteria is called?

Bacteriophages or phages

The production of new viruses occurs within the?

Bacterial cell

What are T2 phages?

A type of bacteriophage that infects E. coli and consists of protein and DNA

How is infection initiated?

Infection is initiated when a virus attaches to a host cell's surface and injects its genetic material

32P = ?

35S = ?

1. Protein

2. DNA

What are isotopes?

Chemical elements that have the same # of protons, but differing neutrons. They are physically distinguishable but have chemically identical forms

What are radioactive isotopes?

Radioactive isotopes are variants of chemical elements that have an unstable nucleus and emit radiation during their decay process

What is transfection?

A method used to introduce nucleic acids into cells

Which part of the phages—its DNA or its protein—serves as the genetic material and is transmitted to phage progeny?

The DNA of the phages serves as the genetic material that is transmitted to phage progeny

What is extranuclear inheritance?

Transmission of genetic information to offspring through cytoplasm not nucleus

Mitochondrial DNA comes from?

Usually from one parent, the mother

Uniparental inheritance?

Inheriting genes from only one parent, typically referring to mitochondrial or plastid DNA transmission

If there is a mutation in a mitochondrial gene, it is passed from?

A mother to all of her children; sons will not pass it on, but daughters will pass it on to all of their children

DNA absorbs UV at?

Protein absorbs UV at?

DNA: 260 nanometers

Protein: 280 nanometers

High UV can lead to?

High mutation frequency

High UV leading to high mutation frequency demonstrates?

That DNA is diverse and able to transform—making it able to be genetic material

What is plasmid?

A small, circular DNA molecule found in bacteria that replicates independently of chromosomal DNA and can carry genes

What are restriction enzymes (endonucleases)?

Proteins that cut DNA at specific sequences, allowing for genetic manipulation, recombinant DNA, and cloning

Why does RNA serve as the genetic material in some viruses?

Because it can replicate quickly and directly code for proteins, allowing viruses to evolve rapidly, also some viruses have RNA core not DNA

DNA is a polymer composed of?

one or two polynucleotide chain

What do nucleotides consist of?

• Phosphate group

• Nitrogenous base

• Pentose sugar

How many oxygen bonds does the phosphate group have?

Four oxygen bonds

What gives DNA its overall negative charge

The negatively charged phosphate group

What links the adjacent sugar molecule in the DNA strand?

The phosphodiester bond

The phosphate group forms the?

Backbone of DNA strands

In gel electrophoresis, why does it move toward the positive electrode?

DNA is negatively charged due to the phosphate backbone, so it is attracted to the positive electrode

What are the two nitrogenous bases?

Pyrimidines and purines

What bond is used to repair DNA?

Glycosidic bond

Purines vs Pyrimidines?

Purines:

• Double-ring structure (nine-member ring)

• Adenine and Guanina

Pyrimidines:

• Single ring structure (six-member ring)

• Cytosine

• Thymine

• Uracil

Uracil is?

Only in RNA

Pentose sugar carbons in DNA/RNA 1’ to 5’

• 1’ = base attachment

• 2’ = DNA vs RNA difference = DNA has no O on 2’ but RNA does

• 3’ = Phosphate attachment

• 4’ = Ring structure

• 5’ = Phosphate attachment

Nucleoside vs Nucleotide

A nucleoside consists of a sugar and a nitrogenous base

Nucleotide includes a sugar, a nitrogenous base, and one or more phosphate groups

What is the source of energy for cells?

ATP

Signal transduction, protein synthesis, and other processes rely heavily on?

GTP

Why are purines paired with a pyrimidine?

They resulted in a uniform width consistent with the X-ray data

What is Chargaff’s rule?

States two findings:

• The base composition of DNA varies between species

• In any species the number of A and T bases is equal, and the number of G and C bases is equal

A + G = ?

T + C

How many hydrogen bonds are in purines and pyrimidines?

Purines: 2 hydrogen bonds

Pyrimidines: 3 hydrogen bonds

Nitrogenous base pairs are held together by?

Hydrogen bonds

Why does DNA run 5’ to 3’?

DNA polymerases can only add nucleotides to the 3' end during replication, ensuring the correct synthesis of the DNA strand.

The two strands of the DNA double helix are held together by?

hydrogen bonds between complementary nitrogenous bases

What interacts in the major groove?

Proteins and DNA sequences

Where is genetic information stored?

In sequence of bases along the DNA molecule.

Nucleotides are linked together covalently hoq?

through phosphodiester bonds that connect the 3’ hydroxyl group of one sugar and the 5’ phosphate attached to the next

The 3’ end carries an? The 5’ end carries a?

An unlinked OH- group attached to the 3’ position on the sugar ring

A free phosphate group attached to the 5’ position on the sugar ring

Which side does a nucleotide get added to on DNA?

The 3’ end of the growing DNA strand

If there is no hydroxyl on 2’ or 3’ on ribose sugar, what could happen?

DNA synthesis would terminate because there is no electrophile to attack the nucleophile

Double stranded DNA/RNA can denature due to?

Heat or stress