Biology - Chapter 12

transformation

process where 1 strain of bacteria is changed by genes from another strain of bacteria

Bacteriophage

virus that infects bacteria

bacteriophage attaches to the surface of the bacterial cell and injects its genetic information into it. The phage DNA is incorporated into the bacterial DNA and the phage uses the bacterial cell to produce new bacteriophages.

how bacteriophages work

to store, copy, and transmit genetic information in a cell

DNA's roles (3)

storing information

foremost job: contain all instructions for determining what and organism will be and the process of developing from a single cell to an adult.

copying information

before a cell divides it must make complete copy of every gene for the new cell.

transmitting information

genes must be transmitted from one generation to the next.

deoxyribonucleic acid

DNA stands for \___

nucleotides joined into long strands/chains by covalent bonds.

DNA is made of \___

nucleotides

Nucleic acids are made of \___

5 carbon sugar, a phosphate group, and a nitrogenous base

3 basic components of nucleotides

nitrogenous base

term for a base that contains nitrogen

adenine, thymine, cytosine, and guanine

DNA's 4 nitrogenous bases

the sugar group of one nucleotide and the phosphate group of the next nucleotide.

In DNA, covalent bonds form between \___

\[A]\=[T] and [C]\=[G]; in DNA, the amount of adenine and thymine found are equal and the amount of cytosine and guanine are equal.

Chargaff's rule

double helix

the shape of DNA; 2 DNA molecules twist around each other like a ladder.

double helix explains

1\.) Chargaff's rule of base pairing, 2.) how two strands are held together, and 3.) how DNA can function as a genetic carrier

anti-parallel strands

2 strands of DNA run in opposite directions

holds 2 strands of the double helix together; hydrogen bonds form only between certain nitrogenous bases. These weak bonds allow the structure to separate.

Why is hydrogen bonding in DNA important?

base pairing

What do we call the following: adenine pairs with thymine, cytosine pairs with guanine

Each base on one strand pairs with only one base on the opposite strand; each strand has information necessary to reconstruct the other half (strands are complementary)

how does base pairing in double helix explain how DNA can be copied?

replication

a copying process which duplicates the DNA

unzipping

a process (mediated by enzymes) which separates the two strands of DNA, allowing 2 replication forks to form.

unzipping the DNA, breaking the hydrogen bonds, and unwinding 2 strands

role of DNA Helicase enzymes in replication

DNA polymerase

enzyme that joins individual nucleotides to produce and proofread a new DNA strand.

telomeres

DNA at tips of chromosomes which is difficult to replicate

telomerase

an enzyme which helps replicate the telomere region by adding short repeated DNA sequences to telomeres; helps prevent genes from being damaged or lost

nucleosomes

beadlike structures of DNA and histones

in the S phase

When does DNA replication occur?

prokaryotic DNA replication

starts in a single spot and goes around in 2 directions until the entire chromosome is copied

eukaryotic DNA replication

begins at many different spots on the DNA molecule and proceeds in 2 directions until the entire chromosome is copied

Single - stranded binding protein

proteins that bind to the freshly split DNA molecule to keep the two strands apart.

Leading Strand

Strand of freshly copied DNA which is continuously made

Lagging strand

Strand of freshly copied DNA which is discontinuously made - resulting in fragments of DNA which will need to be strung together later.

Okazaki fragments

Disjointed pieces of DNA which are created on the lagging strand.

Alfred Hershey and Marsha Chase

Used radioactive materials on bacteriophages to see which material got passed on to bacteria cells, DNA or proteins. Found that DNA was the molecule responsible.

Oswald Avery

Scientist who, with his team, found the molecule which results in transformation by meticulously destroying one molecule at a time.

Frederick Griffith

Scientist who studied the r-strain and s-strain of bacteria and how it influenced mice.

GCAT

What would the complementary DNA strand be if the original strand's sequence is CGTA?

Rosalind Franklin

Scientist who conducted x-ray diffraction on DNA to discover it was a double helix shape

Watson and Crick

Scientists who first build a proper model of the DNA molecule

Erwin Chargaff

Scientist who discovered the amount of adenine and thymine are always equal, as well as the amounts of guanine and cytosine.

Circular

The shape of a bacteria cell's DNA

In the cytoplasm

Where a bacteria cell's DNA can be found

in the nucleus

Where a eukaryotic cell's DNA can be found.

Adenine and Guanine

The bases known as the purines.

Thymine and Cytosine

The bases known as the pyrimidines.

Uracil

uracil binds to adenine via two hydrogen bonds (replaces thymine)

Ribose

Carbohydrate

Phosphate Group

phosphate group is important in living things in different ways. Firstly, it is an important structural component of nucleotide, which is the basic structural unit of DNA and RNA. Secondly, it is a component of energy-rich molecules, such as ATP.

Nucleotide

a compound consisting of a nucleoside linked to a phosphate group. Nucleotides form the basic structural unit of nucleic acids such as DNA.

Nucleic Acid

large biomolecules, essential to all known forms of life.

mRNA

Messenger RNA