Transcript Genetics - sciencephs

Welcome to Semester 2
Topics
 Genetics
 Classification
 Viruses/Bacteria
 Very brief – plants and fungi
 Animal Development
 Animal Phyla
 Human Body
 Fresh Start for your Semester 2 Grade
 Full effort, come in for help, get homework
done, take notes, study for tests…set goals
for a higher grade
Regents Biology
Agendas Out
 Plan for this week – write down your
homework (use your agendas this
semester – they help!)
 Semester 1 Final Exam – if you want to
go through the test, you may come in
on your own time to check your
answers (you will be given key to check
with)
Regents Biology
Zebra
 Like our fingerprints – no two
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patterns are exactly the same
3 different species – each
species does have a general
pattern
Stripes distort distance at dawn
and dusk – tricks predators
Social animals – graze
together, groom each other
Some herds can have over a
thousand members
Look-out for each other and
protect the wounded of their
group
Regents Biology
Cucumber Genetics
 In about 2 weeks we will be tasting cucumber
cotyledons to determine whether they are the
bitter or non-bitter variety – then we will collect
data to determine the genes that code for
bitter/non-bitter and their frequency
 Today, you will be planting 1 seed in a pot of soil
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– don’t place seed too deep in soil
Water your plant
Label your name and hour on the pot/cup
WASH HANDS AFTER PLANTING
Regents Biology
Why do we look the way we
do?
Genetics
*study of passing on
of characteristics
from parents to
offspring
Regents Biology
2006-2007
Inheritance of chromosomes
 Meiosis = making sex cells (egg and sperm)
 Egg + sperm  zygote
meiosis
egg
zygote
sperm
Regents Biology
fertilization
mitosis &
development
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?)
Regents Biology
eye color
(blue or
brown?)
Effect of genes
 Genes come in different versions
brown vs. blue eyes
 brown vs. blonde hair
 alleles

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
Regents Biology
Genes affect what you look like
X
bb
Bb
Regents Biology
BB
Bb
Bb
Where did the blue eyes go??
Bb
Genes affect what you look like…
X
bb
Bb
Regents Biology
Bb
Bb
bb
Why did the blue eyes stay??
bb
Genes affect what you look like…
X
Bb
BB or Bb BB or Bb BB or Bb
Bb
bb
Where did the blue eyes come from??
Regents Biology
How does this work?
 Paired chromosomes have same kind of
genes

but may be different alleles
eye
color
(blue?)
hair
color
Regents Biology
eye
color
(brown?)
hair
color
Yunnan Snub-nosed Monkeys
 Old world monkeys
 Live in small part of China
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mountains, and a small colony is
found in Tibet
Endangered
Specialist feeders – eat only
lichens growing on the bark of
pine trees
Named from short, stumpy nose
Live high up in mountain forests,
up to 4700 meters up!
World’s highest living non-human
primates
Live in groups of 20-60
Little is known about them – hard
to study!
Not discovered until the 1990’s!
Regents Biology
The Father of Genetics
 Gregor Mendel – first person to predict
how traits pass between generations
Studied pea plants
 Self-pollination and cross-pollination
 Studies 1 trait at a time - Monohybrid
 Studies short vs. tall plants over several
generations, then also studies other
plant traits separately

Regents Biology
Generations
 P1 = Parent
 F1 = First Filial (first set of offspring)
 F2 = Second Filial (second set of
offspring)
Regents Biology
Extending Mendelian genetics
 Mendel worked with a simple system
peas are genetically simple
 most traits are controlled by single gene
 each gene has only 2 version

 1 completely dominant (A)
 1 recessive (a)
 But its usually not that simple!
Regents Biology
Traits are inherited as separate units
 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
 Sex cells are haploid (1 set of
chromosomes)
1 from Mom
homologous chromosomes
1 from Dad
Regents Biology
B
Making gametes
BB = brown eyes
bb = blues eyes
Bb = brown eyes
BB
B
b
bb
b
 brown is dominant over blue
 blue is recessive to brown
B
Bb
Remember meiosis!
Regents Biology
b
B
How do we say it?
2 of the same
Homozygous
BB = brown eyes
bb = blues eyes
homozygous dominant
homozygous recessive
2 different
Heterozygous
Bb = brown eyes
Regents Biology
BB
B
b
bb
b
B
Bb
b
Genetics vs. appearance
 There can be a difference between
how an organism looks & its
genetics

appearance or trait = phenotype
 brown eyes vs. blue eyes

genetic makeup = genotype
 BB, Bb, bb
2 people can have the same appearance but
have
different genetics: BB vs Bb
Regents
Biology
Traits Inventory
 Let’s check some of your traits and
alleles you have
 Traits Inventory Packet
Regents Biology
Punnett squares (predict possible offspring)
Bb
x
Bb
male / sperm
female / eggs
X
Regents Biology
B
b
BB
Bb
Bb
bb
B
b
Genetics vs. appearance
How were these
brown eyes made?
eye
color
(brown)
eye
color
(brown)
eye
color
(brown)
eye
color
(blue)
vs.
B
BB
Regents Biology
B
Bb
B
b
Woof! Woof!
Any Questions?
Regents Biology
2005-2006
Dog Genes and Pea Pod WS
 Let’s practice what we just went over!
 Let’s do one Punnet Square Together –
then take 8-10 minutes to complete the
rest of the worksheet (both sides)
Regents Biology
2005-2006
Monohybrid Cross Worksheet
 Due Thursday – you will have some
time to work tomorrow if you finish lab
early
Regents Biology
2005-2006