Week 22Week 22 Genetic ChangesGenetic Changes

Ch. 11.3 pg 296Ch. 11.3 pg 296

MutationMutation

Changes in the DNA sequenceChanges in the DNA sequence

A piece of chromosomebreaks off and is lost.

A piece of a chromosomebreaks off and reattachesin reverse order.

A broken piece attaches to a nonhomologous chromosome.

cancercancer

Diseases believed to be caused Diseases believed to be caused by changes in the genes that by changes in the genes that control the cell cycle control the cell cycle

See pg 211See pg 211

4 Mutations may occur 4 Mutations may occur duringduring

• DNA replication (during interphase)DNA replication (during interphase)

• Transcription (making mRNA) Transcription (making mRNA)

• cell division (mitosis), or cell division (mitosis), or

• Exposure to external agents (mutagens)Exposure to external agents (mutagens)

Point mutationPoint mutation

Change in a single base pair in DNA, Change in a single base pair in DNA, affects only one codonaffects only one codon

frameshift mutationframeshift mutation

When a single base is When a single base is addedadded or or deleteddeleted from DNA, from DNA, changes all following changes all following codonscodons

_____________ mutation_____________ mutation

When sections of chromosomes When sections of chromosomes break and rejoin incorrectly or break and rejoin incorrectly or not at allnot at all

A piece of chromosomebreaks off and is lost.

A piece of a chromosomebreaks off and reattachesin reverse order.

A broken piece attaches to a nonhomologous chromosome.

Chromosomal Chromosomal

MutagenMutagen

Any thing that may Any thing that may cause a change cause a change in the genetic in the genetic codecode in DNA in DNA

3 causes of mutagens3 causes of mutagens

• RadiationRadiation

• Chemical, and Chemical, and

• High temperatureHigh temperature

And now the quizAnd now the quiz

_____________ mutation_____________ mutation

When sections of chromosomes When sections of chromosomes break and rejoin incorrectly or break and rejoin incorrectly or not at allnot at all

A piece of chromosomebreaks off and is lost.

A piece of a chromosomebreaks off and reattachesin reverse order.

A broken piece attaches to a nonhomologous chromosome.

11

2 __________2 __________

Any thing that may cause a change in Any thing that may cause a change in the genetic code in DNAthe genetic code in DNA

3 ________, ________3 ________, ________

Two causes of mutationsTwo causes of mutations

4 ________4 ________

Diseases believed to be caused Diseases believed to be caused by by changes in the genes that changes in the genes that control the cell cycle control the cell cycle

See pg 211See pg 211

5 ________ mutation5 ________ mutation

Change in a single base pair in DNA, Change in a single base pair in DNA, affects only one codonaffects only one codon

6 _________6 _________

Changes in the DNA sequenceChanges in the DNA sequence

A piece of chromosomebreaks off and is lost.

A piece of a chromosomebreaks off and reattachesin reverse order.

A broken piece attaches to a nonhomologous chromosome.

7 ___________ mutation7 ___________ mutation

When a single base is When a single base is addedadded or or deleteddeleted from DNA, from DNA, changing all following changing all following codonscodons

8) When do mutations 8) When do mutations happen?happen?

2 examples2 examples• errors in ___________ of DNA errors in ___________ of DNA

• ___________ (making mRNA) ___________ (making mRNA)

• cell division, or cell division, or

• external agents (mutagens)external agents (mutagens)

9 ______ RNA9 ______ RNA

• Supplies amino acids to the Supplies amino acids to the ribosomal RNA (rRNA)ribosomal RNA (rRNA)

10 ___________10 ___________

• The assembly line for producing The assembly line for producing proteins, bonds amino acids proteins, bonds amino acids togethertogether

11 ____________11 ____________

When enzymes make an mRNA When enzymes make an mRNA copy of a section of DNA (gene)copy of a section of DNA (gene)

RNA

gene

IntronIntronss

Sections of gene that are Sections of gene that are exexpressedpressed

Sections of a gene that are NOT expressedSections of a gene that are NOT expressed12 _____________

expressed

Not expressed

_______________ _______________ proposed that DNA proposed that DNA is composed of two is composed of two

strands twisted strands twisted together in a together in a

double ____.double ____.

1313

helixhelix

14 _________14 _________

The two kinds of The two kinds of nnucleic ucleic aacids, cids,

are made of these are made of these

They consist of 3 molecules bonded togetherThey consist of 3 molecules bonded together

a phosphate group a phosphate group

a sugar, a sugar,

and a nitrogenous baseand a nitrogenous base

DNA and RNA

codon / base / amino acid codon / base / amino acid

• A group of three nitrogenous A group of three nitrogenous _____s in a gene that _____s in a gene that codecode for an for an ______ acid is called a ____________ acid is called a ______

baseamino15

16 _________16 _________

A process which A process which converts mRNA converts mRNA into a proteininto a protein

tRNA

mRNA

rRNA

Amino acid

protein

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