Honors Bio - Unit 10

DNA (deoxyribonucleic acid)

The molecule that carries genetic information; structured as a double helix.

Nucleotide

The building block of DNA/RNA, consisting of a sugar, a phosphate group, and a nitrogenous base.

Helical / Helix

The twisted ladder shape of DNA

Antiparallel

The orientation of DNA strands where they run in opposite directions (5′ to 3′ vs. 3′ to 5′).

Base Pairing

The rule that Adenine pairs with Thymine (or Uracil in RNA) and Cytosine pairs with Guanine.

Chromatin

A substance within a chromosome consisting of DNA and protein (histones).

Chromosome

A threadlike structure of nucleic acids and protein found in the nucleus, carrying genetic information in the form of genes.

Gene

A specific segment of DNA that codes for a protein.

James Watson & Francis Crick

Scientists credited with discovering the double-helix structure of DNA.

Rosalind Franklin

The scientist whose X-ray diffraction images (Photo 51) were critical to discovering the DNA structure.

Erwin Chargaff

• Developed "Chargaff's Rules," stating that [A]=[T] and [G]=[C].

DNA replication

The process of making an identical copy of a DNA molecule.

Semi-conservative

The mechanism of DNA replication where each new DNA molecule consists of one "old" strand and one "new" strand.

Helicase

The enzyme that "unzips" the DNA double helix by breaking hydrogen bonds.

DNA polymerase

The enzyme that adds new nucleotides to the growing DNA strand and proofreads for errors.

RNA primer

A short strand of RNA that serves as a starting point for DNA synthesis.

Leading & Lagging strands

The leading strand is synthesized continuously; the lagging strand is synthesized in short bursts.

Okazaki fragments

Small sections of DNA formed on the lagging strand during replication.

Ligase

The enzyme that "glues" DNA fragments (like Okazaki fragments) together.

Denaturation

• The process of separating the two strands of DNA (often via heat).

RNA (ribonucleic acid)

A single-stranded nucleic acid involved in protein synthesis.

Transcription

The process of copying a segment of DNA into mRNA.

RNA polymerase

The enzyme responsible for creating mRNA from a DNA template.

mRNA

The messenger that carries the genetic code to the ribosome

tRNA

Transfers / brings amino acids to the ribosome

Translation

The process where ribosomes use mRNA and tRNA to build a protein.

Codon

A 3-base sequence on mRNA

Anticodon

The complementary 3-base sequence on tRNA

Protein synthesis

The multi-step process of creating functional proteins from DNA instructions.

Amino acid

The monomer (building block) of proteins.

Polypeptide

A chain of amino acids linked by peptide bonds.

Primary structure

The specific sequence of amino acids in a polypeptide chain.

Protein

A functional biological molecule made of one or more polypeptide chains.

Mutation

Any change in the DNA sequence

Mutagen

An agent (like UV light or chemicals) that causes genetic mutations.

Point mutation

A mutation affecting only one or very few nucleotides in a gene sequence.

Substitution

A mutation where one base is swapped for another.

Frameshift mutation

A mutation caused by insertion or deletion that shifts the "reading frame" of the genetic message.

Chromosomal mutation

A mutation that involves changes in the number or structure of whole chromosomes.

Deletion

Loss of a part of a chromosome or DNA sequence.

Duplication

Production of one or more copies of a gene or chromosome region.

Insertion

The addition of one or more nucleotide base pairs into a DNA sequence.

Translocation

When a piece of one chromosome breaks off and attaches to another.

Aneuploidy

A condition where a cell has an abnormal number of chromosomes (e.g., 45 or 47 instead of 46).

Polyploidy

A condition in which an organism has extra sets of chromosomes (common in plants).

Nucleotide

What is the monomer of DNA?

Erwin Chargaff

Who helped us learn which bases partner together?

Rosalind Franklin

Who took a picture of DNA using x-ray crystallography?

Helix (not double)

Rosalind Franklin helped determine that DNA's shape is a...

James Watson & Francis Crick

Who built a model of DNA and won a Nobel prize?

c. Has adenine-guanine pairs

Which of the following does NOT describe the structure of DNA?

a. Double helix

b. Nucleotide polymer

c. Has adenine-guanine pairs

d. Sugar-phosphate backbone

Nucleotide

What is the name of the monomer that makes up nucleic acids?

b. An amino acid

A nucleotide does NOT contain…

a. A sugar

b. An amino acid

c. A nitrogen base

d. A phosphate group

c. T=A and G=C

Which of the followings shows the correct pair of bases?

a. A=C and T=G

b. G=A and C=T

c. T=A and G=C

d. T=A and C=G

True

T or F: Nucleotides can occur in any order in DNA.

False

T or F: Nitrogen bases bond to sugars and phosphates.

True

T or F: Sugars bond to nitrogen bases and phosphates.

Hydrogen bonds

What type of bond forms between nitrogenous base pairs?

Chromosome

A tightly coiled, compact, and organized structure of DNA = ?

46

How many total chromosomes do humans have?

Replication

The process of DNA duplicating itself = ?

DNA helicase

This enzyme unwinds and unzips DNA during replication...

DNA ligase

This enzyme joins fragments of DNA together to make them a continuous strand...

DNA polymerase

This enzyme adds nitrogen bases to the new DNA strand during replication...

Primase

This enzyme adds an RNA primer to help identify where replication should start...

TGACA

What would the complementary sequence of DNA be for ACTGT during replication?

Adenine and guanine

Which nitrogen bases are purine bases?

Cytosine and thymine

Which nitrogen bases are pyrimidine bases?

D

Which letter best represents the replication fork?

11

Which number best represents the lagging strand?

10

Which number best represents the leading strand?

7

Which number best represents an Okazaki fragment?

True

T or F: Replication is semiconservative because every new DNA helix contains one strand of old DNA and one new strand.

Amino acid

What is the monomer of a protein?

DNA replication

Which process is shown in the diagram

Transcription

Which process is shown in the diagram?

Translation

Which process is shown in the diagram?

Phenylalanine

Which amino acid is coded for by the mRNA codon UUC?

AUG

Which mRNA codon is methionine?

TAC TTG

Reverse transcribe the following sequence into DNA: AUG AAC

met - asn - stop

Translate the following sequence: AUG AAC UGA

A complementary copy of mRNA

What is the end product of transcription?

A growing protein chain

What is the end product of translation?

A codon

The three base sequence on mRNA = ?

An anti-codon

The three base sequence on a tRNA = ?

GCAT

Which nitrogenous bases are found in DNA?

UAGC

Which nitrogenous bases are found in mRNA?

Carries instructions from the nucleus to the ribosomes

What is the function of mRNA?

Carries amino acids to the ribosome

what is the function of tRNA

30

If a protein had 10 amino acids, how many nucleotides were transcribed?

TCA TTG

What is the complementary strand of DNA to the sequence AGT AAC?

RNA

Which molecule has the structural design of a single helix?

RNA polymerase

Which enzyme is responsible for transcribing DNA into mRNA?

Polymerase chain reaction

Which process is used to make millions of copies of a specific region of DNA?

All of the above

Which of the following could the process of PCR be used for?

a. Detecting and identifying viruses

b. Analyzing genetic variation

c. Paternity testing

d. Crime scene analysis

Heat

What variable drives the PCR process?

DNA has a negative charge

In gel electrophoresis, DNA pieces move through a gel because...

DNA fingerprint

Gel electrophoresis is often used to produce a...

Shorter fragments

During gel electrophoresis, which DNA fragments travel further in the gel?

Separates DNA fragments by size

What does gel electrophoresis do?