slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Mutations PowerPoint Presentation
Download Presentation
Mutations

Loading in 2 Seconds...

play fullscreen
1 / 38

Mutations - PowerPoint PPT Presentation


  • 41 Views
  • Uploaded on

Mutations. General Definition Long Notes : Any change in DNA sequence is called a mutation. Abbreviated Notes (AN) : Mutation (mut) = DNA sequence (seq) change. General Definition. General Definition Long Notes : Mutations may affect only one gene, or they may affect whole chromosomes.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Mutations' - sybil


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
general definition

General Definition

Long Notes:

  • Any change in DNA sequence is called a mutation.

Abbreviated Notes (AN):

  • Mutation (mut) = DNA sequence (seq) change
General Definition
general definition1

General Definition

Long Notes:

  • Mutations may affect only one gene, or they may affect whole chromosomes.

(AN):

  • Mut – 1 gene or whole chromosome
General Definition
types

Types

Long Notes:

  • There are three basic types of mutations:
    • Point Mutation
    • Frameshift Mutation
    • Chromosomal Mutation

(AN):

  • 3 types mut.:
    • Point Mut. (PM)
    • Frameshift Mut. (FM)
    • Chromosomal Mut. (CM)
Types
point mutations

Point Mutations

Long Notes:

  • A point mutation is a change in a single base pair in DNA.

(AN):

  • PM = change in 1 base pair in DNA
Point Mutations
point mutations1

Point Mutations

Long Notes:

  • A change in a single nitrogenous base can change the entire structure of a protein because a change in a single amino acid can affect the shape of the protein.

(AN):

  • PM = 1 amino acid (AA) change, can change protein shape
Point Mutations
pm graphic

The effects of point mutations

PM Graphic

mRNA

Normal

Protein

Stop

Replace G with A

Point mutation

mRNA

Protein

Stop

frameshift

Frameshift

Long Notes:

  • A mutation in which a single base is added or deleted from DNA is called a frameshift mutation because it shifts the reading of codons by one base.

(AN):

  • FM = +/- 1 base, causes shift in codons
Frameshift
frameshift graphic
Frameshift Graphic

Frameshift mutations

Deletion of U

mRNA

Frameshift mutation

Protein

frameshift1

Frameshift

Long Notes:

  • This mutation would cause nearly every amino acid in the protein after the deletion to be changed.

(AN):

  • FM – causes most AA in protein after +/- to be wrong
Frameshift
chromosomal mut

Chromosomal Mutations

Long Notes:

  • Few chromosomal mutations are passed on to the next generation because the zygote usually dies.

(AN):

  • CM – zygote usually dies
Chromosomal Mut
chromosomal mut1

Chromosomal Mutations

Long Notes:

  • In cases where the zygote lives and develops, the mature organism is often sterile and thus incapable of producing offspring.

(AN):

  • CM – if lives, usually sterile
Chromosomal Mut
chromosomal mut w g

Chromosomal Mutations

Long Notes:

  • When a part of a chromosome is left out, a deletion occurs.

(AN):

  • CM – part left out = deletion

ABCDEFGH

A B C E F G H

Deletion

Chromosomal Mut w/g
chromosomal mut w g1

Chromosomal Mutations

Long Notes:

  • When part of a chromatid breaks off and attaches to its sister chromatid, an insertion occurs.
  • The result is a duplication of genes on the same chromosome.

(AN):

  • CM – gets duplicate part from sister chromatid = insertion

A B C B C D E F G H

A B C D E F G H

Insertion

Chromosomal Mut w/g
chromosomal mut w g2

Chromosomal Mutations

Long Notes:

  • When part of a chromosome breaks off and reattaches backwards, an inversion occurs.

(AN):

  • CM – part flipping around = inversion

A D C B E FG H

A B C D E F G H

Inversion

Chromosomal Mut w/g
chromosomal mut w g3

Chromosomal Mutations

Long Notes:

  • When part of one chromosome breaks off and is added to a different chromosome, a translocation occurs.

(AN):

  • CM – part breaks off & sticks to another chromosome = translocation
Chromosomal Mut w/g

A

B

C

D

E

F

G

H

W

X

A

B

C

D

E

F

G

H

X

Y

Z

Y

Z

W

Translocation

general results

General Results

Long Notes:

  • Mutations in eggs or sperm affect future generations by producing offspring with new characteristics.

(AN):

  • Mut. egg/sperm = pass offspring
General Results
general results1

General Results

Long Notes:

  • Mutations in body cells affect only the individual and may result in cancer.

(AN):

  • Mut. body cells = cancer (maybe)
General Results
reproductive cells

Reproductive Cells

Long Notes:

  • The mutation may produce a new trait or it may result in a protein that does not work correctly.

(AN):

  • maybe new trait, maybe bad protein
Reproductive Cells
reproductive cells1

Reproductive Cells

Long Notes:

  • Sometimes, the mutation results in a protein that is nonfunctional, and the embryo may not survive.

(AN):

  • protein doesn’t work, embryo might die
Reproductive Cells
reproductive cells3

Reproductive Cells

Long Notes:

  • In some rare cases a gene mutation may have positive effects.

(AN):

  • + effects rare
Reproductive Cells
somatic cells

Somatic Cells

Long Notes:

  • Damage to a gene may impair the function of the cell.
  • When that cell divides, the new cells also will have the same mutation.

(AN):

  • Cell might not work right.
  • Divides – new cells have mut.
Somatic Cells
somatic cells1

Somatic Cells

Normal

Cell

Mutation

Normal

Cell

Mutated

Cell

Normal

Cell

Normal

Cell

Mutated

Cell

Mutated

Cell

Normal

Cell

Normal

Cell

Normal

Cell

Normal

Cell

Mutated

Cell

Mutated

Cell

Mutated

Cell

Mutated

Cell

Somatic Cells
somatic cells2

Somatic Cells

Long Notes:

  • Some mutations of DNA in body cells affect genes that control cell division.
  • This can result in the cells growing and dividing rapidly, producing cancer.

(AN):

  • Mut. might affect genes for mitosis.
  • Too much growth/division = cancer.
Somatic Cells
causes

Causes

Long Notes:

  • Mutations can be caused by errors in replication, transcription, cell division, or by external agents.

(AN):

  • Mut. from replication, transcription, cell div. or ex. agents.
Causes
causes1

Causes

Long Notes:

  • Some mutations seem to just happen, perhaps as a mistake in base pairing during DNA replication.
  • These mutations are said to be spontaneous.

(AN):

  • Spontaneous mut. “just happen”.
Causes
causes2

Causes

Long Notes:

  • Any agent that can cause a change in DNA is called a mutagen.
  • Mutagens include radiation, chemicals, and even high temperatures.

(AN):

  • Mutagen – causes mut., radiation, chems, high temps
Causes
causes3

Causes

Long Notes:

  • Forms of radiation, such as X rays, cosmic rays, ultraviolet light, and nuclear radiation, are dangerous mutagens because the energy they contain can damage or break apart DNA.

(AN):

  • Radiation = Xrays, cosmic rays, UV light, nuclear rad. (all high energy)
Causes
causes4

Causes

Long Notes:

  • The breaking and reforming of a double-stranded DNA molecule can result in deletions.

(AN):

  • Deletions from break/remake DNA
Causes
causes5

Causes

Long Notes:

  • Chemical mutagens include dioxins, asbestos, benzene, and formaldehyde, substances that are commonly found in buildings and in the environment.

(AN):

  • Chemicals = dioxins, asbestos, benzene, formaldehyde; in buildings & environment
Causes
causes6

Causes

Long Notes:

  • Chemical mutagens usually cause substitution mutations.

(AN):

  • Chems – usually substitution mut.
Causes
repairing dna

Repairing DNA

Long Notes:

  • Repair mechanisms that fix mutations in cells have evolved.
  • Enzymes proofread the DNA and replace incorrect nucleotides with correct nucleotides.

(AN):

  • Evolved repair to fix mut. like enzymes to proofread/ fix DNA
Repairing DNA
repairing dna1

Repairing DNA

Long Notes:

  • These repair mechanisms work extremely well, but they are not perfect.
  • The greater the exposure to a mutagen such as UV light, the more likely is the chance that a mistake will not be corrected.

(AN):

  • Good, not perfect.
  • More mutagen, more chance of mistake.
Repairing DNA
question

Any change in DNA sequences is called a _______.

Question

A. replication

B. mutation

C. transcription

D. translation

The answer is B.

question1

Which is more serious, a point mutation or a frameshift mutation? Why?

Question

A frameshift mutation is more serious than a point mutation because it disrupts more codons than a point mutation.

question2

Why are chromosomal mutations rarely passed on to the next generation?

Question

Few chromosomal changes are passed on to the next generation because the zygote usually dies. If the zygote survives, it is often sterile and incapable of producing offspring.