Unit 6A Test Review

​HS-LS1-1: Construct an explanation based on evidence for how the structure of DNA determines the structure of proteins which carry out the essential functions of life through systems of specialized cells.

HS-LS3-1: Ask questions to clarify relationships about the role of DNA and chromosomes in coding the instructions for characteristic traits passed from parents to offspring.

​

Unit 6 - DNA​Standards & Objectives

​

​Protein Synthesis: Transcription & Translation

​Protein Synthesis

Reorder

#2 - List the following steps, in order, for protein synthesis

• DNA unzips between the base pairs.

• A ribosome attaches to the mRNA.

• tRNA carries amino acids to the ribosome and attaches them to the mRNA strand.

• Amino acids are linked together with peptide bonds.

1

2

3

4

• 1
• 2
• 3
• 4

Reorder

#2 - Now reorder the following images, in order, for protein synthesis

1

2

3

4

• 1
• 2
• 3
• 4

64 codons can code for 20 amino acids, so some codons code for the same amino acid.

​

​20 Amino Acids Exist

​

Multiple Choice

 #3 - How many amino acids does the human body use to form all types of protein?

• 4

• 20

• 64

• 1,200

​Replace this with your body text.

​Duplicate this text as many times as you would like.

​All provided templates can be reused multiple times.

​

Replace this with a header

​Substitution Mutation

Multiple Choice

#1 - What would happen to the amino acid sequence if cytosine was substituted for thymine during DNA replication?

• The entire segment of DNA would be affected.

• The sequence could code for the wrong amino acid during translation.

• The cytosine base would pair with adenine when the DNA was replicated.

• There would be no effect on the DNA.

​Some text here about the topic of discussion.

All of these mutations can have dramatic results depending on the genes that are affected, however, the Frameshift Mutations (insertions & deletions) are more ​serious because a large part of the DNA is affected.

​Some text here about the topic of discussion.

​4 Types of Chromosomal Mutations

​

​Point Mutations: Mutations that involve a change in a single base.

​ Substitution mutations (silent, nonsense, missense) occur ​when one gene in a base is replaced with another base which affects one amino acid in the protein structure.

A specific type of neutral mutation in DNA that does not have an observable effect on the phenotype​.

The base change still codes for the same amino acid.

​

​Some text here about the topic of discussion.

​Silent Mutation

Multiple Choice

#8 - Which of the following mutations would be most likely to have a harmful effect on an organism?

• a substitution of a thymine for an adenine

• all mutations have a harmful effect on organisms

• there is not enough information to know whether a mutation would be harmful

• a deletion of 3 bases near the center of a gene

 It causes the production of abnormally thick mucus, leading to the blockage of the pancreatic ducts, intestines, and bronchi and often resulting in respiratory infection; mutations in one codon that produces the cystic fibrosis transmembrane conductance regulator (CFTR) protein.

​​Cystic Fibrosis

​Hemophilia is caused by a mutation, in one of the genes, that provides instructions for making the clotting factor proteins needed to form a blood clot. This change or mutation can prevent the clotting protein from working properly or to be missing altogether. These genes are located on the X chromosome.

​​Hemophilia

A severe hereditary form of anemia in which a mutated form of hemoglobin distorts the red blood cells into a crescent shape at low oxygen levels. It is most common among those of African descent; genetic disorder caused by a mutation in both copies of a person's HBB gene.

​​Sickle Cell Anemia

​

Multiple Choice

#4 - Which disease is caused by the deletion of one codon (3 base pairs) in a DNA molecule?

• Cystic Fibrosis

• Hemophilia

• Sickle Cell Anemia

​A genetic engineering tool that uses ​a CRISPR sequence of DNA and its associated protein to edit the base pairs of a gene.

Benefits: to modify DNA with greater precision than existing technologies.​

Risks: the Cas9 enzyme, which is supposed to slice a specific DNA sequence, will also make cuts in other parts of the genome that could result in mutations that raise cancer risk​.

​

​Clustered Regularly Interspaced Short Palindromic Repeats

​CRISPR

​

Multiple Choice

#5 - What benefit does using the CRISPR technique have in creating GMOs?

• CRISPR can result in infertile hybrids.

• Precise traits can be chosen to produce viable organisms more quickly.

• Diversity within species can continue to increase through crossbreeding.

• It eliminates all risk of mutation.

​Inheritance pattern in which one allele is dominant over the other and completely masks the

​phenotype of the recessive allele when at least one dominant is present in the genotype

​Complete Dominance

Multiple Choice

#6 - What is the phenotype of a mouse with the genotype Bb?

(B = black fur, b = brown fur)

• black fur

• brown fur

• black & brown fur

• spotted fur

Multiple Choice

#7 - A tall, heterozygous pea plant is crossed with another tall heterozygous pea plant. (Tt x Tt) What is the probability that the offspring will be a short plant (tt)?

• 25%

• 50%

• 75%

• 100%

Multiple Choice

A tall, heterozygous pea plant is crossed with another tall heterozygous pea plant. (Tt x Tt) What is the probability that the offspring will be a homozygous tall plant (TT)?

• 25%

• 50%

• 75%

• 100%

Multiple Choice

A tall, heterozygous pea plant is crossed with another tall heterozygous pea plant. (Tt x Tt) What is the probability that the offspring will be a heterozygous tall plant (Tt)?

• 25%

• 50%

• 75%

• 100%

​The interaction between genes that influence a phenotype. It occurs when an allele of one gene interferes with the expression of another gene.

​

​Epistasis

​the allele of one is masked by another

​BB or Bb is black, bb is brown. A recessive epistatic gene, E, results in a yellow coat no matter what black or brown genes are present. When homozygous recessive, ee, blocks the expression of the black and brown alleles!

​Epistasis

Multiple Choice

#10 - Epistasis is observed when the allele of one gene masks the effects of another gene. What color would a dog's fur be if its genes are aabb?

• brown

• black

• yellow

• white

Viruses are not considered alive and do not have the characteristics of a living thing.

Viruses must hijack a host cell to reproduce.

The host cell is used to make copies of the viral DNA or RNA and create new 'baby' viruses that are released to infect more cells.​

​

​Viral Replication

Multiple Choice

#11 - How are new viruses made?

• sexual reproduction

• asexual reproduction

• viral DNA or RNA copied by viral cells

• viral DNA or RNA copied by a host cell

Virus - ​

​an organism consisting of only nucleic acid and protein that uses other cells in order to replicate and make more viruses

​

​Some text here about the topic of discussion.

​Provirus - DNA from a virus that is incorporated into the host cell's DNA

​

Multiple Choice

#12 - Compare and contrast a provirus and viral DNA

• A provirus is viral DNA incorporated into the host cell's DNA

• A provirus is the host cell's DNA that has been destroyed

• A provirus is newly replicated viral DNA after injection

• A provirus is bacterial DNA incorporated into the viral DNA

Cause: Rhinovirus

Spread: Direct contact with infected respiratory droplets​

Cure: No cure because the viral genome mutates quickly making it difficult to develop a vaccine for it!​

​

​Some text here about the topic of discussion.

​Common Cold

Multiple Choice

#13 - Why is the common cold virus difficult to cure in humans?

• It attacks white blood cells that fight off foreign bodies

• It possesses a viral genome that mutates very quickly

• It is a spherical-shaped virus with many protein receptors

• It is caused by a special type of virus called a retrovirus

-Reverse Transcription: Copies viral RNA into DNA​

​-Other viruses use DNA to make RNA to make proteins.

​-HIV attacks white blood cells

-New medicines reduce the concentration of the virus in the blood.

-People are living longer​.

Spread by risky behaviors: ​unprotected sex & sharing needles.

Myths: spread by insect bites, ​swimming in a pool or kissing someone with HIV

​Some text here about the topic of discussion.

​HIV is a RETROvirus

​

Multiple Choice

#14 - What function makes the HIV virus unique?

• It copies the information for reproduction from RNA back into DNA

• It attack neurons in the nervous system and causes paralysis

• It attacks and destroys red blood cells in the bodies of its host organisms

• It has viral DNA that is transmitted through indirect contact with infected persons

Match

#15Q. Compare and contrast the traits of viruses, and bacteria. Is a virus considered a living thing?

A. Bacteria are _1_-celled living organisms with DNA. Viruses are not truly _2_. They are made of a section of DNA or RNA enclosed by a protein shell. Bacteria reproduce by doubling their DNA and organelles and splitting into _3_ cells. Viruses multiply within a living _4_cells, and _5_reproduce without a host.

• 1

• 2

• 3

• 4

• 5

one

living

two

host's

cannot

• one

• living

• two

• host's

• cannot

Match

#16 Q. Why does hemophilia typically affect males more than females?

A. Hemophilia is a recessive disorder that affects the _1_ chromosome. Males receive an X from their mother and a _2_ from their father. A female parent can be a _3_ (X^RX^r) for hemophilia _4_ the disorder. Rarely, a female with two recessive alleles (X^rX^r)

_5_ the disorder.

• 1

• 2

• 5

• 4

• 3

X

Y

will have

won't have

carrier

• X

• Y

• will have

• won't have

• carrier

Multiple Choice

#9 - Which statement best describes why Punnett squares are useful?

• Used to predict the most likely allele combinations of the parents in a cross.

• Used to predict how recessive alleles are inherited.

• Used to predict how dominant alleles are inherited.

• Used to predict all possible allele combinations and their frequencies in offspring.

Match

#17Q. Explain what is meant by: The lactose (lac) operon in E. coli is an example of a gene that is repressed when lactose is not available in a cell.

A. When lactose _1_ present in a cell, the repressor protein _2_ to the operon and prevents transcription of the lac genes. When lactose __ present in the cell, the repressor

_4_ to the operon, and transcription of the lac genes is turned _5_.

• 1

• 2

• 3

• 4

• 5

is not

binds

is

no longer binds

on

• is not

• binds

• is

• no longer binds

• on

Multiple Choice

#19 - Which genetic modifications help provide food for a growing population?

• GMO crops immune to pesticides & herbicides

• GMO animals with higher meat & milk output

• GMO crops that are resistant to drought

• All of these.