regents biology 2006-2007 genetics why do we look the way we do?
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![Page 1: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/1.jpg)
Regents Biology 2006-2007
Genetics
Why do we look the way we do?
![Page 2: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/2.jpg)
Regents Biology
Inheritance of chromosomes Egg + sperm zygote
egg
sperm
zygote
fertilizationmitosis &
development
meiosis
![Page 3: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/3.jpg)
Regents Biology
Inheritance of genes On the chromosomes passed from
Mom & Dad to offspring are genes may be same information may be different information
eye color(blue or brown?)
eye color(blue or brown?)
![Page 4: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/4.jpg)
Regents Biology
Effect of genes Genes come in different versions
brown vs. blue eyes brown vs. blonde hair alleles
![Page 5: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/5.jpg)
Regents Biology
Genes affect what you look like
XBBbb
Bb Bb Bb Bb
Where did the blue eyes go??
![Page 6: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/6.jpg)
Regents Biology
Genes affect what you look like…
XBbbb
Bb Bb bb bb
Why did the blue eyes stay??
![Page 7: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/7.jpg)
Regents Biology
Genes affect what you look like…
XBbBb
BB or Bb BB or Bb BB or Bb bb
Where did the blue eyes come from??
![Page 8: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/8.jpg)
Regents Biology
What did we show here? Genes come in “versions”
brown vs. blue eye color alleles
Alleles are inherited separately from each parent brown & blue eye colors are separate &
do not blend either have brown or blue eyes, not a blend
Some alleles mask others brown eye color masked blue
![Page 9: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/9.jpg)
Regents Biology
How does this work?
eye color(brown?)
hair color
hair color
eye color
(blue?)
Paired chromosomes have same kind of genes but may be different alleles
![Page 10: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/10.jpg)
Regents Biology
Traits are inherited as separate units
1 from Mom
1 from Dad
For each trait, an organism inherits 2 copies of a gene, 1 from each parent a diploid organism inherits
1 set of chromosomes from each parent diploid = 2 sets of chromosomes
homologous chromosomes
![Page 11: Regents Biology 2006-2007 Genetics Why do we look the way we do?](https://reader036.vdocuments.us/reader036/viewer/2022062320/56649d7d5503460f94a5ff8f/html5/thumbnails/11.jpg)
Regents Biology
Making gametes
BB = brown eyesbb = blues eyesBb = brown eyes
BB
bb
Bb
brown is dominant over blue
blue is recessive to brown
Remember meiosis!
B
B
b
b
B
b
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Regents Biology
How do we say it?
BB = brown eyesbb = blues eyes
Bb = brown eyes
2 of the sameHomozygous
2 differentHeterozygous
BB
B
B
bb
b
b
Bb
B
b
homozygous dominanthomozygous recessive
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Regents Biology
Punnett squaresBb x Bb
male / sperm
fem
ale
/ eg
gs
X
BB
Bb bb
BbB
b
B b
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Regents Biology
Genetics vs. appearance There can be a difference between
how an organism looks & its geneticsappearance or trait = phenotype
brown eyes vs. blue eyesgenetic makeup = genotype
BB, Bb, bb
2 people can have the same appearance but have different genetics: BB vs Bb
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Regents Biology
Genetics vs. appearance
eye color(brown)
eye color
(brown)
eye color(blue)
eye color
(brown)
vs.
BB
B
BBb
B
b
How were these brown eyes made?How were these brown eyes made?
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Regents Biology 2005-2006
Woof! Woof!Any Questions?