DNA Structure ands Genome Organizations

What is the Central Dogma of Moelcular Biology

True or False:

The central dogma is often refined

true

What did Oswald Avery’s Experiment look for?

What type of molecule contains the genetic information of a cell?

What was used in the model avery system of determining what molecule carried the genetic information

streptococcus pneumoniae

What were the two type of bacteria in streptococcus pneumoniae

• smooth (s) cells

• rough ( r ) cells

Describe the Smooth (S) cells in the experiment?

• have a polysaccharide capsule

• look smooth under microscope

• virulent (cause disease)

Describe the Rough (R) cells

• no capsule

• looks rough

• non-virulent

What is significant about the capsule in the smooth cells

it protects the bacteria from the immune system and without it bacteria would get destoryed so the capsule is deemed as a suvival trait- therefore it needs to be genetically controlled

In the Avery Experiment:

Avery built on earlier work showing:

👉 Dead S cells could “transform” R cells into S cells

This process is called:

Bacterial transformation

• Cells take up external DNA

• Their traits change

What is the significance of this?

information move between cells and something from dead cells is still biologically active

Step 2: Avery’s Key Experiment

Avery asked:

👉 What exactly is the “transforming material”?

He took dead S cells and separated their components:

• Proteins

• Lipids

• Carbohydrates

• RNA

• DNA

Then he tested each one.

What were the critcal results when DNA was present

R-cells → transformed in to S cells

Step 2: Avery’s Key Experiment

Avery asked:

👉 What exactly is the “transforming material”?

He took dead S cells and separated their components:

• Proteins

• Lipids

• Carbohydrates

• RNA

• DNA

Then he tested each one.

What were the critical reseults when DNA was destroyed

there was no transformation

Step 2: Avery’s Key Experiment

Avery asked:

👉 What exactly is the “transforming material”?

He took dead S cells and separated their components:

• Proteins

• Lipids

• Carbohydrates

• RNA

• DNA

Then he tested each one.

What were the critical results when proteins were destroyed?

transformation still happened

What is being described:

• unicellular

• no nucleus

• DNA is in the cytoplasm

Prokaryotes

What is being described:

• unicellular or muticellular

• DNA in nucleus

Eukaryotes

What are DNA and RNA comprised of

nucleotides

what is it calle dwhen something is a polymer of several nucleotides

oligonucleotides

what is it called when it is a polymer of many nucleotides

polynucleotides

What connects each nucleotide in a polynucleotide

phosphodiester linkage

How can the sequence of polynucleotide be abbreviated

only using the base attached to each nucleotide

where do the phosphodiester linkages connect

at the 3’ OH of 1 nucleotide and the 5’ phosphate of the next neculeotide

What direction are nucleotides labeled

from the 5’→3’

What is the first of Chargaffs Rules

DNA has concentrations in which A=T and G=C

What is the second rule of chargaffs rules

Base composition # varies between species

Based on on Chargaff’s third rule answer this true or false question:

Base composition # is the same in different cells within an indivudual organism

true

what is the fourth of chargaffs rules

base composition (%) does NOT change with age, nutrition, and environment

How is Rosalind Franklin so significant

she used X ray diffraction to show that DNA is helical with a consistent diameter

What does X-ray diffraction do?

bend (diffract) in different directions based onthe location of atoms in a macromolecule

What is the chemical structure of DNA

• its a repeating unit

• DNA contains two unbranched polynucleotide chains i

What is the repeating unit of DNA

2'-deoxyribonucleoside 5'-monophosphates (dNMP)

DNA contains two unbranched polynucleotide chains.

What type of orientation is it

antiparallel

DNA contains two unbranched polynucleotide chains.

Two chains interact by what type of bonding?

hydrogen bonding

DNA contains two unbranched polynucleotide chains

• Antiparallel orientation

• Two chains interact by hydrogen

bonding

What type of base pairing is it

Watson-Crick-Franklin base pairing

What is the sugar phosphate part of DNA called

backbone

When seperating DNA strand, what is it called when you seperate two DNA strands

denaturing

What is the temperature at which a solution of DNA is 50% denatured

T(m)= melting temperature

How do complementary single strands of DNA anneal to each other?

by base pairing

True or False:DNA is a long, flexible molecule

True

In a living cell, >99% of the DNA is in what conformation?

the B-DNA conformation

Which type of helix is B-DNA

a right handed helix

How do base pairs lay out in B-DNA

they are flat and perpindicular to the backbone

In B-DNA which portion of bases are on the interior

hydrophobic portions and base stacking interactions

In B-DNA where are the base pairs exposed in

the major and minor grooves

What are the alternative forms of DNA

A-DNA and Z-DNA

Which alternative form of DNA is being described:

• the conformation of dehydrated DNA

• a good structural model of double stranded and RNA-DNA hybrid

A-DNA

Which form of alternative DNA is:

• <1% of cellular DNA

• seen in regions with high G-C content

• a left handed helix

Z-DNA

True or false: very small amounts of other conformations of DNA exist in eukaryotic cells called:

• cruciform

• triplex

• quadruplex

true

What is typically a linear single-stranded polynucleotide chain

RNA

what type fo sugar backbone does RNA have

a ribose sugar phosphate backbone

In RNA what replaces Thymine

Uracil

which direction does the RNA sequence move in

5’→3’

What make the helical shape in RNA

base stacking interactions

What can RNA base pair with

complementary regions of either RNA or DNA

Wat does the RNA structure resemble?

the A-DNA conformation

What orientation are the strands of RNA

antiparallel

what type of pairing is allowed wheN RNA base pairs with itself or another RNA moelcule

G-U base pairing

RNA moelcules form complex structures

Styructures come from the internal base pairing within an RNA

complex secondary and tertiary structure

What is being described:

A ____ contains:

• the DNA encoding a fucntional RNA or protein

• the regulatory elements controlling its expression

gene

What is the complete set of geentic material present in a cell or organism

genome

What does E. Coli have

A single circular chromosome ( DNA molecule that encodes genes) with the position of genes fixed within a species

between a prokaryote and eukaryotes which has the lowest amount of DNA, number of chromosomes, and approximate number of genes

prokaryotes

between a prokaryote and eukaryotes which has the highest amount of DNA, number of chromosomes, and approximate number of genes

eukaryotes

The largest amount of DNA is found within what specific part of a eukaryotes

diploid

The largest amount of chromosomes is found within what specific part of a eukaryotes

diploid

The largest amount of the number of genes is found within what specific part of a eukaryotes

haploid

A human cell has 46 _____________

linear chromosomes

What do eukaryotes have bound to chromosomal DNA

proteins (histones)

True or False: The position of genes are charcateristic of our species

true

The positions of the genes are characteristic of our species.

What is an example of this?

the EDN1 gene is always located a 6p24

What is the significance of cystic firbosis

a tiny DNA change as simple as 3 nucleotides missing removes a single acid from CTFR

What does a missing piece of an amino acid from CFTR do?

it prevents the protein from folding correctly so the cell destroys it before it ever reaches the membrane

What happens if CTFR is not present

This small deletion disrupts the folding of the CFTR protein, impairing chloride transport and leading to thick mucus buildup in lungs and other organs. Chloride ions are not reabsorbed from the sweat duct back into the body, causing a high concentration of chloride (and sodium) to remain in the sweat.