Genetics, Biotechnology and DNA EOC Review

GENETICS

BENCHMARKS

SC.912.L.16.1 Use Mendel’s laws of

segregation and independent
assortment to analyze patterns of
inheritance

SC.192.L.16.2 Discuss observed

inheritance patterns caused by
various modes of inheritance,
including dominant, recessive,
codominant, sex-linked, polygenic,
and multiple alleles

INHERITANCE

Traits are specific

characteristics inherited
from parents

Genes are the factors that

determine traits

The different forms of a

gene are called alleles

GENETICS

Humans have somewhere between 20,000 and 30,000
genes between our 23 chromosomes.

We have two copies of every chromosome (diploid),
meaning that we have 2 copies of every gene.

Each different form of a gene is called an allele, and we
can have the same alleles or different alleles for each gene.

If the alleles are the same, we are referred to as
homozygous; if the alleles are different, we are referred to as
heterozygous.

Your genotype describes the genes you have; the
phenotype is the physical appearance

MENDELS
LAWS OF
HEREDITY

1. Law of Dominance

• - the dominant allele will prevent the recessive allele

from being expressed

• - recessive allele will appear when it is paired with

another recessive allele in the offspring

2. Law of Segregation

• - gene pairs separate when gametes (sex cells) are

formed

• - each gamete has only one allele of each gene pair

3. Law of Independent Assortment

• - different pairs of genes separate independently of

each other when gametes are formed (Anaphase II in
Meiosis)

LAW OF SEGREGATION

 States that allele pairs separate or segregate during gamete formation, and

randomly unite at fertilization.

LAW OF INDEPENDENT ASSORTMENT

-states that allele pairs separate independently during the
formation of gametes.

GENOTYPE
ACTUAL
ALLELES AN
INDIVIDUAL
HAS FOR A
TRAIT

Homozygous

 Both alleles are the same

 Ex. BB or bb
Heterozygous

 Both alleles are

different

 Ex. Bb

PHENOTYPE

 The physical characteristic displayed by the individual (ex.

brown eyes, Hemophiliac)

Multiple Choice

Which of the following describes a part of a phenotype?

• Gg

• Homozygous

• Having freckles

• Heterozygous

Multiple Choice

Which of the following describes an organism that has two different alleles for a trait?

• Heterozygous

• Homozygous

• Dominant

• Recessive

STEPS TO SOLVE A GENETIC PROBLEM

1.

Determine the parents genotype

2.

Separate the alleles

3.

Draw a Punnett Square

4.

Calculate the probability of the offspring genotype

5.

Calculate the probability of the offspring phenotype

TEST CROSS

 used to determine the phenotype of an unknown dominant individual

 uses a homozygous recessive individual as the “test”

R: Dominant allele produces round seeds

r: Recessive allele produces wrinkled seeds

Homozygous (pure) two alleles with the same genetic information RR or rr

Heterozygous (hybrid) two alleles with different information Rr

Two round seeded plant produced a wrinkled seeded plant because it

received two recessive alleles for wrinkled seed.

DOMINANT AND RECESSIVE
INHERITANCE

 Dominant alleles are expressed, if present, and recessive are

hidden

Homozygous

Heterozygous

Identical factors-

-TT,tt

Different Factors – Tt (hybrid)

Genetic Terms

MONOHYBRID CROSS

Multiple Choice

In genetics research, what is the purpose of a test cross?

• to determine the phenotypes of the parents

• to determine the genotypes of the parents

• to determine whether or not two parents could produce viable offspring

• to determine how many offspring can be produced by two parents.

Multiple Choice

A geneticist crossed tall pea plants and obtained 971 tall pea plants and 315 short pea plants in the F1 generation. What were the genotypes of the parents that produced the offspring in the Punnett square shown, if T is the allele for tall, and t is the allele for short?

• Tt

• TT

• tt

• TtTt

Multiple Choice

The Punnett square describes the potential offspring of a cross. What phenotypes will be shown by the offspring?

• All offspring will show the recessive phenotype for this trait.

• All offspring will show the dominant phenotype for this trait.

• Half of the offspring will show the dominant phenotype and half will show the recessive phenotype.

• Three fourths of the offspring will show the dominant phenotype and one fourth will show the recessive phenotype.

DIHYBRID CROSS

 A dihybrid cross involves two

genes and is done the exact
same way as a basic dominant
recessive cross.

9:3:3:1

Multiple Choice

Identify the choice that best completes the statement or answers the question.

A gardener crosses a true-breeding tall tomato plant bearing red fruit with a true-breeding dwarf tomato plant with yellow fruit. In tomatoes, tall vine (T) is dominant to dwarf vine (t) and red fruit (R) is dominant to yellow fruit (r).

Assume that the two genes controlling the “tall vine” and “red fruit” traits are on two different pairs of chromosomes.

What are the expected phenotype ratios in the F2 generation?

• 9 tall vine/red fruit; 3 tall vine/yellow fruit; 3 dwarf vine/red fruit; 1 dwarf vine/yellow fruit

• 4 tall vine/red fruit; 3 tall vine/yellow fruit; 1 dwarf vine/red fruit

• 2 tall vine/red fruit; 4 tall vine/yellow fruit; 2 dwarf vine/yellow fruit

• 16 tall vine/red fruit; 9 tall vine/yellow fruit; 3 dwarf vine/red fruit; 1 dwarf vine/yellow fruit

Multiple Choice

Several matings between the same male black guinea pig and female brown guinea pig produce a total of 12 brown and 14 black guinea pigs. If black is dominant and brown is recessive, what are the genotypes of the parents?

• BBxbb

• Bbxbb

• BBxBb

• BbxBb

POLYGENIC INHERITANCE

 Traits that are affected by many genes

are called polygenic traits.

 Because these traits are controlled by

many genes, the traits show a large
spectrum of characteristics with most
individuals expressing an intermediate
phenotype.

 For example, skin color is a polygenic trait

CODOMINANCE

Codominance, a cross between organisms with two different phenotypes

produces offspring with a third phenotype in which both of the parental traits
appear together.

CODOMINANCE

 Codominance occurs when both alleles are dominant

 this means that if both alleles are present, both alleles

will be expressed (as opposed to only one allele)

 Ex. Roan animals

CODOMINANCE IN BLOOD TYPES

Universal Donor

Universal Recipient

Multiple Choice

What are the possible genotypes of a person with type A blood?

I. IAIA

II. IAIB

III. IAi

• III. only

• I. and II.

• I. and III.

• I., II. and III.

Multiple Choice

Which is an example of codominance?

• A smooth-seeded pea plant and a wrinkled-seeded pea plant produce smooth-seeded pea plants.

• A white rabbit and a black rabbit produced a white and black rabbit.

• A blue-eyed man and a brown eyed woman produce a blue-eyed child.

• A color-blind woman and a man with normal vision produce a color-blind son.

Multiple Choice

A couple has five children, all with blood type A. The mother’s blood type is O, and the father’s blood type is A. Based on this information, which describes the most probable genotype of the father?

• Diploid

• Haploid

• Heterozygous

• Homozygous

INCOMPLETE
DOMINANCE

Incomplete dominance a

cross between organisms
with two different
phenotypes

produces offspring with a third

phenotype that is a blending
of the parental traits.

Incomplete dominance occurs

when neither allele is
dominant to the other.
Instead, the alleles in
combination show an
intermediate trait

Multiple Choice

Some flowers show incomplete dominance. If RR = white and R’R’ = red, which phenotypic ratio would be expected in the offspring of two pink flowers?

• 1 red : 2 pink : 1 white

• 0 red : 4 pink : 0 white

• 3 red : 0 pink : 1 white

• 4 red : 0 pink : 0 white

SEX-LINKED
INHERITANCE

Chromosomes 1-22 are known as autosomes – males and females have the
same genes on these chromosomes. The 23rdchromosome is the sex
chromosome. Women are XX while men are XY.

Men are more likely to show sex-linked recessive traits because they only have
one X chromosome.

A female may have the recessive allele, but it may be hidden by the dominant
allele on the other X chromosome.

For a recessive trait, women can be normal (XX), carriers of the recessive trait
(XXC), or show the trait XCXC).

Men are either unaffected (XY) or show the recessive trait (XCY).

When solving problems, determine whether the question is asking about a child
(use all four boxes in the Punnett square to determine probability) or a specific
sex (only look at the two boxes in the Punnett square that are the same sex.

SEX LINKED TRAITS

 Sex Chromosomes

 Female = XX

 Male = XY

 Sex linked traits are carried on the X

chromosome

 Ex. Hemophilia, red-green

colorblindness

Female

Male

Multiple Choice

Most sex-linked, recessive traits- including hemophilia and color blindness-appear in males. This phenomenon is best explained by which statement?

• Males have an X chromosome with dominant genes.

• Most of the genes on the X and Y chromosomes of males are recessive.

• In males, the recessive sex-linked genes appear only on the Y chromosome.

• In males, the Y chromosome lacks the genes needed to mask the recessive genes on the X chromosome.

Multiple Choice

Which correctly describes a genetic trait that is sex-linked in humans?

• The trait that appears only in males or only in females, but not in both.

• The gene that is always carried on the Y chromosome

• The trait is expressed only during the act of reproduction.

• The trait that is carried on the X or Y chromosome.

GENETIC

DISORDERS

 Genetic disorders are inherited, not acquired.

Many genetic disorders cause death before birth.

 Nondisjunction occurs when homologous chromosomes fail

to separate during meiosis I, causing a gamete to be
diploid or have no chromosomes are all. When this gamete
fuses with a normal gamete, the resulting zygote has 3
copies of the chromosome (trisomy) or one copy
(monosomy). An example of this is Down’s Syndrome
(trisomy 21).

 Translocation occurs when non-homologous chromosomes

crossover.

 Inversion occurs when sections of chromosomes are cut out

and replaced in the opposite orientation as normal.

 Duplication occurs when sections of DNA are duplicated.

 All of these genetic disorders have serious implications for

the health of the child.

KARYOTYPE

 Picture of someone's chromosomes

 Can detect chromosomal disorders

Ex. Down Syndrome,
Klinefelter’s Syndrome, and
Turners Syndrome

Multiple Choice

A karyotype of a human female shows that she has only one sex chromosome. Which genotype would represent her genetic condition?

• XO

• XXX

• XY

• XYY

PEDIGREE

 Similar to a family tree

 Shows pattern of

inheritance of a specific
trait through a family

PEDIGREE CHART

Multiple Choice

Mitochondria are often described as the powerhouses of the cell. Genetic disorders can result when mitochondrial mutations occur. For example, a condition called Kearns-Sayre syndrome is caused by deletions in the mitochondrial DNA. This genetic disorder causes weakness of the muscles and other symptoms because the mitochondria are not able to provide sufficient energy to the cells. The diagram shows the possible phenotypes of children from parents who have the disease. How is Kearns-Sayre syndrome inherited? Select the best explanation.

• Genetic disorders caused by mitochondrial mutations are examples of cytoplasmic inheritance. Only mothers transmit mitochondrial genetic disorders to their children. The male gametes have little cytoplasm. They do not contribute mitochondria to the embryos.

• Genetic disorders caused by mitochondrial mutations are examples of polygenic inheritance, because they are transmitted from fathers to children. Mitochondria are provided by both parents in the cytoplasm of the gametes.

• Mitochondrial genetic disorders are inherited as a dominant trait in the egg cell DNA, causing disease in the child.

• Mitochondrial genetic disorders are inherited as a dominant trait in the sperm cell DNA, causing disease in the child.

Multiple Choice

Huntington’s disease is a dominant trait. What are the chances that a child will develop Huntington’s disease if one parent is heterozygous and the other is normal?

• 0 out of 4

• 1 out of 4

• 2 out of 4

• 3 out of 4

Multiple Choice

A plant nursery only grew one type of tomato plant. All of their tomato plants died from the same disease. What was most likely true of the tomato plant population?

• They had a lot of resistance to disease.

• They had a few plants that were resistant to the disease.

• They had too much variation in their genes.

• They had little variation in their genes.

BIOTECHNOLOGY

•You need to understand how biotechnology
impacts individuals, society, and/or the
environment. You will be given scenarios with
specific examples and asked to determine the
impact.

SC.912.L.16.10 Biotechnology

BIOTECHNOLOGY

 Scientists have the ability to take genes

from one organism and insert them into
another organism. This process is called
genetic engineering.

Scientists use specific enzymes called
restriction enzymes to cut the DNA of
both organisms (must use the same
restriction enzyme to ensure that the
sticky ends match). The reason that
scientists are able to do this is because
the DNA of all organisms is made of the
same nucleotides (adenine, guanine,
cytosine, and thymine).

RECOMBINANT DNA

 Cell with DNA from another source

 Bacteria used to produce human

insulin

 Human gene inserted into bacterial

plasmid

Multiple Choice

Genetic engineers use plasmids. A plasmid is

• A map of a gene

• A cell that is not yet specialized

• A small circular piece of DNA

• An enzyme that can cut DNA into pieces

RECOMBINANT DNA

Insulin for Diabetes

Multiple Choice

Genes for medically important proteins can be cloned and inserted into bacteria, as shown in the diagram below. Why can bacteria recognize a human gene and then produce a human protein?

• DNA replication in bacteria and humans is the same.

• Bacterial cells contain the same organelles as human cells.

• The basic components of DNA are the same in humans and bacteria.

• The cell is composed only of DNA and protein.

Multiple Choice

What is the relationship between DNA and protein in a cell?

• DNA is made up of proteins that are synthesized in the cell.

• Protein is composed of DNA that is stored in the cell.

• DNA controls the production of protein in the cell.

• a disease-resistant plant crossed with a plant that produced a high volume of food

Multiple Choice

A team of scientists splices a human gene into bacterial plasmids. The human gene codes for insulin. Then the scientists use the plasmids to transform bacteria. Their goal is to develop bacteria that will synthesize insulin.

How is it useful for the plasmids to also contain genes for antibiotic resistance?

• The genes for antibiotic resistance increase the rate that bacteria take up the plasmids

• The genes for antibiotic resistance act as genetic markers for identifying the transformed bacteria.

• The genes for antibiotic resistance help activate the gene for insulin.

• The genes for antibiotic resistance help the transformed bacteria survive in their environment.  

BIOTECHNOLOGY

 Scientists can also use restriction enzymes to cut

DNA at multiple sequences and then “run” them
in a process called gel electrophoresis.

 This process allows scientists to separate

sequences of DNA based on size.

 In the real world, scientists use this to identify

people based on their DNA (paternity tests and
crime scenes).

GEL
ELECTROPHORESIS

 Technique used to separate

molecules (DNA or proteins)
based on their size

 Sometimes called a DNA

fingerprint

 Used to analyze and

compare DNA

DNA FINGERPRINTING

Gel Electrophoresis

Multiple Choice

In a class discussion about genetically modified (GM) foods, Jan claims that these foods are safe to eat. She cites scientific studies that compare GM and non-GM foods. The studies provide evidence that the GM foods have no effect on human health.

Which of the following statements provides the strongest argument AGAINST Jan's claim?

• GM foods are relatively new, so their long-term effects cannot be evaluated yet.

• GM plants incorporate genes from bacteria or other organisms.

• Scientists have yet to sequence the complete genome of most GM plants.

• a common set of locations of genes on the DNA molecule

Multiple Choice

The diagram shows the process of making recombinant DNA and using it to transform a bacterial cell. The recombinant DNA is made by inserting a human gene into a bacterial plasmid. Note that the plasmid contains several genes for antibiotic resistance, including ampr, tetr, and ori.

Which is the most likely purpose of the transgenic bacteria that are engineered by this process?

• developing new drugs to fight antibiotic-resistant bacteria

• removing traits of antibiotic resistance from bacteria populations

• using bacteria to produce large quantities of a human protein, such as growth hormone

• No, because each chromosome contains the same three genes.

Multiple Choice

In this procedure, what is the function of the structure labeled ecoRI?

• It is a restriction enzyme that reduces the activity of the plasmid.

• It is a restriction enzyme that cuts both the plasmid and human DNA.

• It is a genetic marker that allows for the selection of transformed bacteria.

• It is a genetic marker that allows for the human gene to be isolated.

HUMAN GENOME PROJECT

 Sequencing of human DNA

 Being used to develop gene

therapies

Multiple Choice

Two individuals each donated a DNA sample for DNA fingerprinting. The diagram shows the same section of the same chromosome from each sample.

In the process of DNA fingerprinting, restriction enzymes were used to cut the DNA into fragments. Each fragment contains either a gene or a section of noncoding repeated sequences between two genes. Then gel electrophoresis was used to separate the fragments.

Suppose the techniques of DNA fingerprinting were applied only to the sections of the chromosomes shown in the diagram. Would the techniques be useful for distinguishing the two samples? Why or why not?

• Yes, because the techniques identify the locations of genes on chromosomes.

• Yes, because the techniques separate DNA fragments by size.

• No, because the three genes have identical nucleotide sequences.

• No, because each chromosome contains the same three genes.

TRANSGENIC
ORGANISM

 An organism with a

gene from another
source

 used to improve food

supply, research, and
healthcare

CLONE

 An organism made from one cell of

another organism

 A genetically identical copy

Multiple Choice

Dog breeders often use the technique of inbreeding. Choosing which of these mating pairs of dogs is an example of inbreeding?

• a male poodle and a female poodle, each with similar traits

• a male poodle and a female collie that are about the same size, but differ in other traits

• a male poodle and a female dachshund that have similar personalities, but differ in other traits

• a male dachshund with a much larger female dog, such as a Great Dane

Multiple Choice

Which of the following is not an advantage of genetically engineered crop plants?

• They can produce their own pesticides

• They grow larger than unmodified crops

• They cannot cause allergic reactions

• a male dachshund with a much larger female dog, such as a Great Dane

Multiple Choice

Luther Burbank bred potatoes that combined a variety of useful traits. One of Burbank's breeding techniques was hybridization. Which cross of potato plants would have been MOST USEFUL for producing a useful strain by hybridization?

• a. a disease-resistant plant crossed with a plant that is not disease resistant

• a plant that is not disease resistant crossed with a plant that produces a low volume of food

• a disease-resistant plant crossed with a plant that produced a low volume of food

• a disease-resistant plant crossed with a plant that produced a high volume of food

Multiple Choice

In many techniques of genetic engineering, a gene from one species is transferred to another species. When the techniques succeed, the gene is functional in its new genome.

Which are the properties, shared by all or nearly all species, that allow these techniques to be successful? Select all of the answers that apply.

• a common use of RNA for carrying genetic information  

• a common molecular structure of the DNA molecule

• a common genetic code for translating genetic information into proteins

• a common set of locations of genes on the DNA molecule

DNA AND RNA

BENCHMARKS

 SC.912.L.16.3 Describe the basic process of DNA replication and

how it relates to the transmission and conservation of the genetic
information
SC.912.L.16.4 Explain how mutations in the DNA sequence may or
may not result in phenotypic change. Explain how mutations in
gametes may result in phenotypic changes in offspring.

 SC.912.L.16.5 Explain the basic processes of transcription and

translation, and how they result in the expression of genes.
SC.912.L.16.9 Explain how and why the genetic cod is universal
and is common to almost all organisms

DNA / RNA

 Carry genetic information

 Made of a chain of nucleotides

 Nucleotides contain a sugar, phosphate, and a

nitrogen base

Multiple Choice

In a DNA molecule, the sides of the staircase are composed of

• Single nucleotides

• Pairs of nucleotides

• Joined sugars and phosphates

• Joined nitrogen bases and phosphates

Multiple Choice

In a DNA molecule, thymine always pairs with

• Cytosine

• Guanine

• Thymine

• Adenine

Multiple Choice

What are the building blocks of DNA?

• Genes

• Nucleotides

• Amino acids

• Ribosomes

Multiple Choice

At what point in the cell cycle does DNA replication occur and why?

• before a cell divides, to provide each of the two resulting cells with a complete set of DNA

• before a cell divides, to ensure that the DNA will fit into the resulting cells

• during cell division, to ensure that the DNA will fit into the resulting cells

• after a cell divides, to provide each of the two resulting cells with a complete set of DNA

DNA / RNA
DNA

 Deoxyribonucleic

acid

 Double stranded

 “Double Helix”

 Four base pairs:

ATGC

 Sugar is Deoxyribose

 Found in nucleus

 (held together by

weak hydrogen
bonds)

RNA

 Ribonucleic acid

 Single stranded

 Four base pairs: AUCG

 Sugar is Ribose

 Three major types of RNA

 (Ribosomal – rRNA;

Messenger – mRNA;
Transfer – tRNA)

 Leaves the nucleus to

carry out functions in
cytoplasm

BASE PAIR RULE

 In DNA,

Adenine always pairs with Thymine,
and

Guanine always pairs with Cytosine

Multiple Choice

If 35% of an organism’s DNA is thymine, what is the percentage of guanine?

• 15%

• 35%

• 70%

• 50%

Multiple Choice

Chargaff's rules of base pairing are explained by which structural feature of DNA?

• Each strand of DNA contains a phosphate and sugar backbone.

• The nucleotides of DNA may appear in a wide variety of sequences.

• DNA is double stranded, and covalent bonds between identical nucleotides hold the strands together.

• DNA is double stranded, and hydrogen bonds between base pairs hold the strands together.

Multiple Choice

A segment of a DNA strand has the following bases: TAC GAT

What is the complementary strand of DNA?

• UAG CAU

• TAG CAT

• ATG CTA

• AUG CUA

Multiple Choice

What did the DNA sequence that produced an mRNA strand with the sequence AGUACA looks like?

• UCAUGU

• AGTACA

• AGUACA

• TCATGT

Multiple Choice

What would happen if a cell divides before DNA replication is completed?

• Daughter cells would receive incomplete genetic information, but would regain lost information in the G1 phase.

• Daughter cells would receive incomplete genetic information, but would regain lost information in the S phase.

• Daughter cells would contain all genes of the parent cell, but would not function normally.

• Daughter cells would receive incomplete genetic information and never regain it, and they may not survive.

Multiple Choice

How does DNA replication differ between eukaryotes and prokaryotes?

• The base-pairing rules are different between eukaryotes and prokaryotes.

• Only prokaryotes rely on enzymes such as DNA polymerase.

• Only eukaryotes rely on enzymes such as DNA polymerase.

• Eukaryotes use multiple replication forks to replicate a larger volume of DNA.

REPLICATION

 Making of an identical strand of DNA

 “semi” conservative

DNA Replication Animation

DNA

The nucleotides in DNA form

long chains. Two chains
linked and twisted like a
spiral staircase. This shape is
called a double helix.
Adenine pairs only with
thymine, and cytosine pairs
only with guanine. The
strands are complementary
to each other.

DNA STRUCTURE

DNA REPLICATION

SUMMARY of DNA Replication

1. The strands separate: Helicase splits the double helix to
unzip the strands of DNA and form replication fork
2. An RNA primer binds to template to begin synthesis
3. DNA polymerase reads the templates and adds
nucleotides to synthesize the new DNA strands
4. DNA ligase seals the gaps between the Okazaki
fragments.

DNA replication results in two identical daughter
molecules each consisting of one old (original) strand and
one newly-synthesized strand.

Multiple Choice

There are three main types of RNA: messenger RNA (mRNA), ribosomal RNA (rRNA), and transfer RNA (tRNA).

Which type or types of RNA contain a copy of the instructions that a gene carries?

• mRNA only

• rRNA only

• mRNA and tRNA

• mRNA, tRNA, and rRNA

Multiple Choice

Which of the following carries amino acids to the site of protein synthesis?

• mRNA

• rRNA

• tRNA

• nRNA

Multiple Choice

A diagram of a cellular process is shown below.

Which of the following identifies the process shown at point Z?

• Translation

• Translocation

• Replication

• Transcription

TRANSCRIPTION AND TRANSLATION

Transcription a
segment of DNA is
copied into RNA
(mRNA)

Translation

TRANSCRIPTION

DNA→mRNA

Occurs in nucleus

Complementary mRNA strand is
produced from a segment of DNA

TRANSLATION

 Connects amino acids in the correct order to make

a protein

 Occurs in the cytoplasm within the ribosomes

A- amino acid
B- tRNA
C- anticodon
D- codon
E- mRNA
F- Ribosome
G-polypeptide

Multiple Choice

Transcription creates an mRNA molecule using DNA as a template. Where does this Occur?

• In the cell membrane

• In the cytoplasm

• In the nucleus

• In the ribosomes

61

Replication

Transcription

Translation

CODON

Sequence of three
mRNA nucleotides
that code for an
amino acid

20 amino acids

DNA sequence: TAC GGA CAT AAC ACC TGC ATC

mRNA sequence: AUG CCU GUA UUG UGG ACG UAG

A

-

U

Multiple Choice

During transcription the DNA base sequence is transcribed into a complimentary mRNA sequence. A codon table like the one shown below lists the amino acids coded for by particular triads of mRNA bases. A segment of DNA has undergone a mutation in which one nucleotide has been changed. The original sequence was ACG and the new sequence is ACA. Use the codon table to determine whether or not this mutation will cause a change in the phenotype of the organism.

• Yes, the phenotype of the organism would change because a new amino acid will be coded for.

• Yes, the phenotype of the organism would change because any change in the DNA sequence will cause a change in phenotype.

• Even though the DNA sequence changed, the sequence still codes for the same amino acid, so no change in phenotype will occur.

• It is impossible to determine if a change in phenotype will occur using only the DNA sequence.

Multiple Choice

A molecule of tRNA includes a sequence of three nitrogenous bases called an anticodon. What is the role of the anticodon in the process of translation?

• The anticodon binds to a codon on rRNA.

• The anticodon binds to a codon on mRNA.

• The anticodon binds to a specific amino acid.

• The anticodon binds to the promoter, a region of DNA.

Multiple Choice

Translation involves several different types of tRNA molecules. Which statement best describes how tRNA molecules assemble amino acids into a polypeptide?

• One tRNA molecule assembles the polypeptide, and the others assist it.

• Three tRNA molecules assemble the polypeptide, and the others assist them.

• Each tRNA molecules assembles a different part of the polypeptide, and all at the same time.

• The different tRNA molecules act in a specific order, one after the other like an assembly line.

Multiple Choice

A scientist puts nucleotide chains of UUUUUU in a test tube under conditions allowing protein synthesis. Soon the test tube is full of polypeptide chains composed only of the amino acid phenylalanine. What does this experiment indicate?

• The amino acid phenylalanine is composed of uracil.

• UUU codes for the amino acid phenylalanine.

• Protein synthesis malfunctions in test tubes.

• Most proteins contain only one type of amino acid.

Multiple Choice

The sequence of DNA below is part of a gene. How many amino acids are coded for by this segment?

5' ATCAGCGCTGGC 3'

• 4

• 8

• 12

PROTEIN SYNTHESIS

An individual’s traits such as hair color and eye color, are determined by

proteins. Proteins are made up of chains of amino acids. DNA codes for 20
amino acids. How these amino acids combine determines the shape and
purpose of the proteins they form.

The information in an organism DNA is used to make proteins. If two of the

base pairs are switched a mutation occurs and a different protein is made.

UNIVERSAL CODE

The genetic code is nearly universal because all organisms:

1. encode their genes using DNA or RNA.

2. use the same codon for the same amino acid.

3. are genetically related to all other organisms.

MUTATIONS

 Change in DNA code

 May cause a change in protein produced

 NOT always harmful

Sickle Cell
Mutation

CANCER

Error in cell growth with causes
uncontrolled cell growth

Has environment and genetic
variables

Multiple Choice

Which relationship is most similar to the relationship below?

tRNA: ribosome

• book: publisher

• truck: factory

• key: lock

• baker: pie

Multiple Choice

A point mutation changes a codon in an mRNA molecule. Will the mutation affect the polypeptide that forms? Why?

• Yes. Each amino acid is specified by only one codon.

• No. The structure of DNA, and not RNA, determines the polypeptide.

• Maybe. Some codons are translated into two or more amino acids.

• Maybe. Some pairs of codons are translated into the same amino acid.

Multiple Choice

The genetic code is universal. This means that

• All organisms can exchange genes

• A given codon always codes for the same amino acid

• Animals have more chromosomes than plant and fungi.

Multiple Choice

Which of the following would most likely cause a mutation?

• the placement of ribosomes on the endoplasmic reticulum

• the insertion of a nucleotide into DNA

• the movement of transfer RNA out of the nucleus

• the release of messenger RNA from DNA