UNIT 14 BIOLOGY

Changes to the sequence of nucleotides in DNA, or changes to chromosomes, are called ________. In an example called a __________ only one base pair is altered. If a base pair is inserted or deleted, the change may cause a ____________.

mutations; point mutation; frameshift mutation

Where does transcription occur in the cell?

nucleus

Insertion

- when a single, extra base is added into the code - frameshift mutation

Translation

Process by which mRNA is decoded and a protein is produced

How many strands are in RNA?

single strand

The process of copying DNA prior to cell division

replication

mRNA (messenger RNA)

a single-stranded RNA molecule that encodes the information to make a protein

Where does translation occur in the cell?

cytoplasm and ribosome

Insertions and deletions are also known as

frameshift mutations

The " language" of RNA is called the __________, and uses three-letter "words" called _________

genetic code, codons

anticodon

group of three bases on a tRNA molecule that are complementary to an mRNA codon

When can mutations be passed to offspring?

in sex cells

RNA uses the sugar _________ instead of deoxyribose

ribose

What is the type of sugar in RNA?

ribose

A sequence of amino acids called _______ is produced during the process of ________. During this process, the __________ of a tRNA molecule binds to a codon of a mRNA molecule.

polypeptide, translation, anticodon

One or more extra whole sets of chromosomes is called _______________, which often is beneficial in plants.

polyploidy

gene expression

process by which a gene produces its product and the product carries out its function

Introns

sequence of DNA that is not involved in coding for a protein

RNA

single-stranded nucleic acid that contains the sugar ribose

Promoter

specific region of a gene where RNA polymerase can bind and begin transcription

Three types of point mutations

substitution, insertion, deletion

Transcription

synthesis of an RNA molecule from a DNA template

RNA contains _________ in place of __________.

uracil, thymine

Translocation

-Chromosomal mutation - when part of one chromosome breaks off and attaches to another

Two categories of mutations

-Gene Mutations - Chromosomal Mutations

Inversion

-chromosomal mutation - Reverses the direction of parts of chromosome

Deletion

-chromosomal mutation -Loss of all or part of a chromosome

Duplication

-chromosomal mutation -extra copy of all or part of chromosome

Deletion

-when a single base is removed from the code - frameshift mutation *** shift the " reading frame" of the genetic message

mutagen

A chemical or physical agent that interacts with DNA and causes a mutation. Ex: smoking

codon

A specific sequence of three adjacent bases on a strand of DNA or RNA that provides genetic code information for a particular amino acid

an organism is exposed to a mutagen, such as x-rays or ultraviolet light. What could be the effect of the mutagen on the organism? Select all that apply. A. The mutagen may disrupt gene function to the harm of the organism. B. The mutagen may change gene function in a way that benefits the organism. C. The mutagen may change the genetic material of the cell from DNA to proteins. D. The mutagen may change the binding between codons and anticodons. E. The mutagen may have little or no observable effect on the organism.

A, B, and E

Judith is developing a computer model of mutations in human DNA. She plans for the model to incorporate one point mutation for every 10 million base pairs of DNA, Which is a rate that is supported by her research. However, her advisor argues that mutations can occur 100 times more frequently under certain circumstances. which would most likely cause the increase in mutation rate that the advisor describes? A. mutagens in the environment, such as tobacco smoke in certain pesticides. B. human cells that have especially large amount of DNA. C. The presence of transcription factors that control gene expression. D. The presence of epigenetic factors that affect gene expression.

A.

Manny is using a computer model to investigate the effects of substitution mutations. The model represents many with a long base sequence for a gene. Manny then select one base for a mutation, such as by substituting cytosine, "C", for adenine, "A" Manny completes many traits of mutations. And most child, the result of the substitution mutation is either no effect, or a polypeptide, in which one amino acid is altered. In one trial, however, the result is a truncated polypeptide. Many of its terminal amino acids are missing. what is the most likely explanation for truncated polypeptide? A. The substituted base cost a frameshift mutation. B. The mutation introduced a stop codon in the middle of the gene. C. The mutation introduced the start codon in the middle of the gene D. The substituted base alter the genetic code.

B.

is it possible for a codon code for more than one amino acid A. Yes B. No

B.

Carly was hired today for a job as a laboratory assistant. She will work for a professor of molecular biology who wants to make new discoveries about genes, DNA, RNA, and their functions. Carly's work will most likely contribute to which of these specific research goals? A. Identifying the molecule that makes up genes B. Describing the role of RNA polymerase in RNA synthesis. C. Determining the links between genes and traits the influence. D. Identifying the types of nucleotides that make up RNA.

C

The diagram shows the effect of a point mutation on a section of a gene. The nitrogenous base adenine ("A") is inserted into the sequence. What best describes this mutation and its affect on the protein that the gene produces? A. It's a missense mutation that changes exactly one amino acid. B. It's a nonsense mutation that has no effect on the protein. C. It's a frameshift mutation that changes many amino acids. D. It is a frameshift mutation that changes exactly one amino acid.

C.

What are the steps of protein synthesis?

DNA ——-> mRNA (transcription) DNA ——> RNA ——> Protein ——> trait (Translation)

What does gene expression do?

Cells control with genes they want to express

By studying the diagram, Percy would most likely to construct an answer to which of these questions? A. how many codons make up a typical mRNA molecule? B. Our specific codons associated with introns and exons? C. which amino acid is most common in a typical protein? D. Are all codons translated into amino acids?

D.

Velma is developing a computer model of translation. Her instructor points out that the model does not include ribosomes or ribosomal RNA. If the model is accurate in other ways, how does the absence of ribosomes and ribosomal RNA e affect it? A. certain amino acids would be missing from the polypeptides B. The polypeptide would be much longer than normal. C. Amino acids would be joined together in an incorrect order. D. Amino acids would not join together, and no polypeptides would form.

D.

Where does protein synthesis occur?

On ribosomes, which are made up of two subunits. The subunits consist of several molecules.

ribonucleic acid (RNA)

Single-stranded nucleic acid that contains the sugar ribose

rRNA (ribosomal RNA)

The form of RNA found in the ribosome

tRNA (transfer RNA)

The form of RNA that carries each amino acid to the ribsome to form the polypeptide chain (protein)

Mutation

The process by which variations are introduced into DNA

Transcription definition #2

The process of copying a base sequence from DNA to RNA

translation definition #2

The process of decoding an mRNA message into a protein

What is the purpose of a stop codon?

To show the polypeptide is complete

The molecule that carries amino acids to the ribosome is called

Transfer RNA

What three code on signal that translation should stop?

UGA, UAA, UAG

Uracil

a nitrogen-containing base found in RNA (but not in DNA); pairs with adenine in RNA.

point mutation

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

deletion mutation

a mutation in which one or more pairs of nucleotides are removed from a gene

What makes up a protein?

amino acids into chains called polypeptides

stop codon

codon that signals to ribosomes to stop translation

genetic code

collection of codons of mRNA, each of which directs the incorporation of a particular amino acid into a protein during protein synthesis

Four types of chromosomal mutations

deletion, duplication, inversion, translocation

RNA polymerase

enzyme that links together the growing chain of RNA nucleotides during transcription using a DNA strand as a template

Exon

expressed sequence of DNA; codes for a protein

Polypeptide

long chain of amino acids that makes proteins