Unit 8 Lesson 3: Genetic Variation from Errors

Question 1

Cell theory

Answer 1

Cell theory states that all organisms are made of cells and that cells reproduce from pre-existing cells

Question 2

Genetic variation can occur from

Answer 2

chromosomal changes that happen during meiosis.

Question 3

Any changes made to the DNA sequence is called a

Answer 3

mutation

Question 4

Chromosomal changes could be in the form of..

Answer 4

Chromosomal changes could be in the form of numeric mutations affecting the number of chromosomes, or structural mutations that alters the way the chromosome is coded.

Question 5

Exmaple of a strucutal mutation

Answer 5

For example, a structural mutation can be an insertion or deletion of a portion of the chromosome. This is why the process of meiosis is important in sexual reproduction.

Question 6

What happenes during Meiosis

Answer 6

Meiosis creates new sex cells, that is, sperm and egg cells. These cells are known as haploid cells because they contain half the chromosomes that normal body cells do. The changes that occur mostly happen during the early stages of development.

Question 7

genetic information is found in the double-stranded structures of

Answer 7

deoxyribonucleic acid, or DNA, in the chromosomes of cells.

Question 8

The strands of DNA contain nucleotide bases that code for

Answer 8

triplet codons.

Question 9

What does each condon of DNA code for

Answer 9

Each codon codes for a particular amino acid. The amino acid patterns become the building blocks for proteins.

Question 10

What must take place before mitosis or meiosis can begin

Answer 10

Before mitosis or meiosis can begin, cells must copy, or replicate, the strands of DNA so they are available for new cells

Question 11

In order for replication to occur, the strands of DNA must

Answer 11

separate

Question 12

How does DNA repliacte

Answer 12

This occurs when an enzyme “unzips” the strand of DNA. Complementary strands are created for each separated strand. This results in two matching chromosomes that are identical to the original chromosome.

Question 13

DNA polymerase

Answer 13

an enzyme that plays a critical role in placing nucleotides in the correct order

Question 14

Role of DNA polymerase

Answer 14

Another enzyme, DNA polymerase, plays an important role during replication by placing the copied nucleotide bases in the correct order.

Question 15

What does DNA polymerase do

Answer 15

DNA polymerase double-checks, or proofreads, the bases as they are added.

Question 16

What does DNA polymerase do if theres a mistake

Answer 16

If there is a mistake, DNA polymerase will “cut out” and release the incorrect nucleotide.

Question 17

What will DNA polymerase do if there a correct base

Answer 17

The correct base will then be added into the sequence.

Question 18

How does a substitution mutation happen

Answer 18

Nucleotide bases are represented by the letters A, T, C, and G, with A and T pairing up and C and G pairing up. If any of the bases are mistakenly exchanged for another, the mutation is called a substitution mutation.

Question 19

Substitution mutation

Answer 19

a nucleotide base is replaced with the wrong corresponding pair

Question 20

Substitution Mutations: if G is added instead of A, the G will pair up with T. What effect could this have

Answer 20

if G is added instead of A, the G will pair up with T. This could create a codon that changes the amino acid being produced. This, in turn, could cause a small change in the protein that is created. Sickle cell anemia could happen

Question 21

Substitution Mutations: What is Sickle cell anemia

Answer 21

Sickle cell anemia is a disorder caused by a substitution mutation, in which a single amino acid is altered in the beta-hemoglobin gene located in red blood cells.

Question 22

Substitution Mutations: What are Silent mutations

Answer 22

Silent mutations are mostly harmless because the substitution creates a codon that still produces the same proteins. This does not result in any change in gene expression, hence it is “silent.”

Question 23

Substitution Mutations: What happens if a substitution creates a “stop” codon

Answer 23

If a substitution creates a “stop” codon, the copied strand will produce an incomplete protein. This type of protein will not be able to function properly. Sometimes this is called a nonsense mutation.

Question 24

Insertion mutations

Answer 24

add extra base pairs to the DNA sequence making it longer than it should be to code specific proteins

Question 25

What do the effects of insertion mutations rely on

Answer 25

Remember that nucleotide codons are found in groups of three, so the effects of this type of mutation depends on the number of bases inserted.

Question 26

(insertion mutations) If the inserted number of bases is not in a multiple of three, what kind of mutation occurs?

Answer 26

If the inserted number of bases is not in a multiple of three, a frameshift mutation occurs, shifting the reading frame for all the codons that follow.

Question 27

What impact can a frameshift mutation have

Answer 27

This mutation can change the entire protein that is made and can lead to serious problems, such as birth defects or no development at all.

Question 28

Frameshift mutation

Answer 28

adding or removing base pairs so that the DNA sequence can no longer be put into exact triplets

Question 29

. A frameshift mutation means that the nucleotides in the DNA sequence can no longer be put into

Answer 29

exact triplets

Question 30

(insertion mutations) In a frameshif mutation what could lead to an essential protein not be coded

Answer 30

There might be one or two bases left which could potentially lead to an essential protein not being coded.

Question 31

If the frameshift mutation occurs towards the beginning of the sequence, what could happen?

Answer 31

If the frameshift mutation occurs towards the beginning of the sequence, then it could potentially result in a completely different translation than the original strand.

Question 32

(insertion mutations) If there is an insertion of a three-base group, what happens

Answer 32

If there is an insertion of a three-base group, then there is no frameshift mutation, and the insertion will potentially have less harmful effects.

Question 33

When do Deletion mutations occur

Answer 33

Deletion mutations occur where sections of DNA are not copied during replication.

Question 34

What impact do Deletion mutations have

Answer 34

This means some parts of a codon may be read incorrectly and the length of the copied gene might change.

Question 35

What is a Point deletion

Answer 35

when one base is deleted in the DNA sequence which can lead to incorrect protein synthesis

Question 36

Cystic fibrosis is an example of a disease that is a result of a

Answer 36

a point deletion on the CFTR gene

Question 37

How does Cystic fibrosis affect somebody

Answer 37

a point deletion on the CFTR gene that affects the proteins that move salt and water in and out of cells, creating mucus buildup in different areas of the body.

Question 38

What impact can the deletion of 1 or 2 bases have

Answer 38

A deletion of one or two bases may also cause a frameshift mutation that can result in changes in the rest of the DNA depending on where in the sequence it occurs.

Question 39

(Deletion mutations) What impact could three or more bases are lost in a gene have

Answer 39

If three or more bases are lost in a gene, entire amino acids can be missing from proteins, which can lead to even more serious functional effects.

Question 40

Many replication errors can contribute to inheritable genetic variations, what are those

Answer 40

changes in genetic material that can be passed to offspring

Question 41

viable errors

Answer 41

changes that can be passed to living offspring

Question 42

viable errors are those that can be passed to the next generation because they allow the offspring to develop and survive. However what downside may viable errors have

Answer 42

However, the inherited genetic variations may result in severe health disorders, a shortened life span, or sterile offspring.

Question 43

Impact od serve replication errors

Answer 43

Most replication errors are so severe they prevent an offspring from developing at all, which means the error is not viable. The offspring will not develop or survive, and thus no inheritable genes are passed on.

Question 44

Look at the following segments of DNA, and describe the types of mutation that occurred.
a) Original: ACT CAT
Mutation: ACT GCAT
b) Original: ATT TGA GCC
Mutation: ATT GAG CC
c) Original: ATT GAC CCT
Mutation: CTT GAC CCT
Reveal Answer

Answer 44

a) insertion mutation and frameshift mutation
b) deletion mutation and frameshift mutation
c) substitution mutation

Question 45

Which of the following will cause frameshift mutations?

insertions only
deletions only
insertions and deletions
substitutions only

Answer 45

insertions and deletions

Question 46

Describe how genetic variation occurs through meiosis.

Answer 46

Genetic variation through meiosis can lead to chromosomal abnormalities in the form of numeric mutations affecting the number of chromosomes, or structural mutations that alters the way the chromosome is coded. For example, a structural mutation can be an insertion or deletion of a portion of the chromosome. As genetic material copies before meiosis, other mutations can occur such as insertion, deletion, substitution, and frameshift mutations.

Question 47

Sometimes mistakes are made when copying DNA. Explain the results of this mistake.

Answer 47

When mistakes are made when copying DNA, mutations can occur. These mutations help contribute to genetic variation in the offspring.

Question 48

Explain the process of replication during cell division.

Answer 48

In replication, the genetic material is copied. The length of DNA that makes up a chromosome is copied to make an identical sister chromatid.

Question 49

Which of the following is the enzyme that assists in placing nucleotides in the correct order?

amylase
DNA polymerase
helicase
primase

Answer 49

DNA polymerase

Question 50

Explain what is meant by a viable error.

Answer 50

A viable error is an error in genetic material. The error can be passed to future generations.

Question 51

Scientists have learned that any fault in the replication of DNA can cause something known as epigenetic changes. What is Epigenome

Answer 51

made of compounds and proteins that attach to DNA and can affect which genes are turned “on” or “off” in the production of certain proteins

Question 52

Epigenetic changes

Answer 52

DNA modifications that do not affect the sequence but the expression of certain genes

Question 53

what can impact epigenome

Answer 53

. Research shows that factors such as a person’s diet, exposure to pollutants, and stress can also impact the epigenome and that these changes are viable errors that may be inherited through the generations.

Question 54

An example of epigenetics is methylation whats what

Answer 54

the attaching of methyl groups (made of one carbon and three hydrogen) to DNA to regulate gene expression

Question 55

What does methylation do

Answer 55

With these groups added to a gene, the gene is turned off, and the protein production from that gene stops.

Question 56

What impact does methylation have on peope

Answer 56

This action can lead to abnormal gene activity, or inactivity, and cause genetic disorders for people with a high risk of some diseases.

Question 57

Under-methylation

Answer 57

Under-methylation – having too few methyl groups to help regulate gene expression that can lead to neurological symptoms and disorders

Question 58

What impact does Under-methylation have on the body

Answer 58

Having too few methyl groups can cause symptoms such as obsessive-compulsive disorder, increased fear, frequent headaches, or poor concentration.

Question 59

What studies have been amd eon Under-methylation

Answer 59

Studies are being conducted to understand the connection between under-methylation and several neurological disorders such as depression, anxiety, autism, schizophrenia, and Alzheimer’s disease.

Question 60

Over-methylation

Answer 60

having too many methyl groups trying to regulate gene expression that can lead to neurological symptoms and disorders

Question 61

What are the symptoms of people who have Over-methylation

Answer 61

Symptoms of people who are have over-methylation include panic attacks, sleep disorders, body aches, food or chemical sensitivities, and paranoia.

Question 62

In similar studies of under-methylation, over-methylation has been linked to neurological disorders such as

Answer 62

depression, anxiety, and schizophrenia.

Question 63

Over-methylation realsionship with sxhizopheria

Answer 63

Roughly 45% of schizophrenic diagnoses show that the patient also has an excess of methyl groups.

Question 64

impactof studying epigenetics

Answer 64

Studying epigenetics can help scientists learn what effects these modifications have on gene function, the production of protein, and human health.

Question 65

Describe how epigenetics can affect the characteristics of organisms.

Answer 65

Epigenetics affects the characteristics of organisms by changing how genes are expressed. Genes may be turned off or on when they do not need to be, and this can affect the health of some individuals.

Question 66

Jose states that he is experiencing body pain, a sensitivity to certain foods, and having trouble sleeping. If tested, which would you most likely see affecting the gene expression in Jose: over-methylation or under-methylation? Explain your reasoning.

Answer 66

Jose seems to be producing too many methyl groups that is affecting his gene expression. The symptoms of over-methylation include body pain, sensitivity to foods, and trouble sleeping.