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GeneticsWednesday/Thursday 1/7-1/8/2015
Agenda: Welcome Back!!
Notes: Intro to Genetics Activity: Brain Pop and Worksheet Activity: Genetic Terms Review Activity: Monster Genetics (due in class)
Homework/Class Work:1. Monster Genetics due Today for 50 Points
(Grade Book)2. Homework: Genetics Practice Problems
worksheet due Friday 1/9/2015 for 10 Points
1. Chimp’s & human’s DNA are 98% identical.
2. The father determines the sex of the offspring.
3. A genetic blood disorder can make your skin look blue.
4. A person may transmit characteristics to their offspring which he/she do not show themselves.
5. Geneticists have created a potato that can self destruct.6. We share 40-50% of our DNA with cabbages7. Scientists estimate that 99.9 percent of the DNA of most
humans is identical.8. Each parent contributes half of their child’s genetic make-up.9. Henrietta Lacks was a woman with a mutation who had
immortal cells, who later died of cervical cancer (kidney injury)
10. Humans share 50% of their DNA with bananas.
THE FIELD OF BIOLOGY DEVOTED TO UNDERSTANDING HOW CHARACTERISTICS ARE PASSED FROM PARENT TO OFFSPRING.
Q3 WK1 D1
Genetics:
Jan. 7, 2013
GREGOR MENDEL (1823 – 1884)
• AUSTRIAN MONK WHO STUDIED MATH & STATISTICS.
• HE BECAME KNOWN AS THE “FATHER OF GENETICS”.
• HE CONDUCTED EXPERIMENTS ON PEA PLANTS.
MENDEL’S PEA PLANT EXPERIEMENTS
• He observed 7 characteristics of pea plants • each characteristic had only 2 contrasting traits.
- height- flower position along the stem- pod appearance- pod color- seed texture- seed color- flower color
MENDEL’S EXPERIMENT
1. GREW ONLY PLANTS THAT WERE PURE FOR EACH TRAIT.
-he had plants self-pollinate for several generations.
2. CROSS-POLLINATED CONTRASTING TRAITS.-ex: he crossed a yellow pod plant with a
green.3. THE 1ST CROSS WAS LABELED AS THE PARENTAL
GENERATION (P).
4. THE OFFSPRING WERE LABELED AS THE F1 GENERATION
5. MENDEL ALLOWED THE F1 GENERATION TO SELF-POLLINATE & THOSE OFFSPRING WERE THE F2 GENERATION.
MENDEL’S RESULTS
• AFTER CROSSING A PURE GREEN PODDED PLANT (P) WITH A PURE YELLOW (P) ALL OF THE OFFSPRING WERE GREEN.
• AFTER THESE OFFSPRING (F1) WERE CROSSED THE RESULTING OFFSPRING (F2) CAME OUT TO A 3 TO 1 RATIO FOR GREEN PODDED PLANTS.
MENDEL’S LAWS
• LAW OF SEGREGATION - - two alleles for a character will separate when a gamete
is formed• LAW OF INDEPENDENT ASSORTMENT: -The factors for different characteristics are not connected
QUESTION
EXPLAIN WHY MENDEL GOT THE RESULTS HE DID WITH THE PARENTAL
GENERATION?
ANSWER
Because the green color is considered dominant & it covers or masks the
yellow color trait (recessive)
QUESTION
If all of the offspring were green and then they were cross pollinated, why didn’t
these offspring come out all green?
ANSWERBecause the offspring from F1 generation carried a hidden yellow factor that could be
passed on to the offspring of F2 generation.
The Testcross
• A genetic procedure devised by Mendel to determine an individual’s actual genetic composition
• A purple-flowered plant can be homozygous dominant (PP) or heterozygous (Pp)
• One cannot tell by simply looking at the phenotype
• One can tell from the results of a cross between the test plant and a homozygous recessive plant
How Mendel used the testcross to detect heterozygotes.