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Week 19, Day Four
HW # 63- Karyotyping project with your group
(in Google Docs). Watch meiosis video
Warm up
What can scientists really tell about you by looking at your
DNA?
Warm up Response
-…
Homework Response/Check
Did you complete the questions at the end of
yesterday’s lab? Self sign off.
• Format Karyotyping Document
• 5 minutes to revise your Mitosis quiz
• Chromosomes, Genes, Alleles
Instructions for the karyotyping homework:
1. Select a SINGLE group member to log into GoogleDocs
2. Make a COPY the Karyotyping homework
3. RENAME: YOUR character_period
4. Share the copy (editing) with your other group
members AND with me
Sam Stubs-1
Norma Nanny-2
Captain Relish-3
Glen Glendora-4
Fred Fleckstone-5
Theresa Thyme-6
Our DNA is very long
?
So how does it all fit into the
nucleus?
It is stored in
chromosomes
Here is a picture of a pair of pig chromosomes.
We can see them because they have been made to
fluoresce.
Pigs have 19 chromosome pairs in total
This is a picture of a male pig’s full set of chromosomes
Humans have 23 pairs of chromosomes in total
Here are some human chromosomes inside a cell,
which have also been made to fluoresce
Different bits of the
chromosomes do
different things.
]
These different bits are
called genes.
http://www.ncbi.nlm.nih.gov
Gene
• A gene is the functional and physical unit of
heredity passed from parent to offspring.
• Genes are pieces of DNA, and most genes
contain the information for making a specific
protein.
Genome
• A genome is all the DNA contained in an
organism or a cell, which includes the
chromosomes plus the DNA in mitochondria
(and DNA in the chloroplasts of plant cells).
• humans have estimated 30-35,000
genes
• other 98% of DNA noncoding –
“junk” or regulatory
http://www.ncbi.nlm.nih.gov
We have 2 copies of every gene,
we get one copy from our dad and the other from
our mum.
Different genes tell us different things,
like what color hair to have, what color eyes to
have & whether to be left or right handed.
Genes are very particular,
like phone
numbers - if you
get a number
wrong they won’t
work!
Fill in the blanks using the words at the bottom:
______ are the basic building blocks for life.
Inside each ______ is one ______ .
Our ______ is stored in the nucleus.
Our DNA is very ______ so it is stored in ______.
Different bits of chromosomes are called
______.
Different genes tell our bodies ______ things .
We have ______ copies of every gene.
______ in our genes cause problems.
different two
errors
DNA
nucleus
cells
chromosomes
cell
genes
long
Traffic light
• I understand that cells are the
basic building blocks for all
living things
• I can relate DNA to genes
and chromosomes
• Are you red, amber or green?
Chromosomes and Heredity
• Heredity = transmission of genetic characteristics from
parent to offspring
– karyotype = chart of chromosomes at metaphase
• 23 pairs homologous chromosomes in somatic cells
(diploid number of chromosomes)
– 1 chromosome inherited from each parent
– 22 pairs called autosomes
– one pair of sex chromosomes (X and Y)
• normal female has 2 X chromosomes
• normal male has one X and one Y chromosome
• Sperm and egg (GAMETES) contain only 23
chromosomes
– fertilized egg has diploid number of chromosomes
2 Basic Things Can Happen Which DNA
1. The ENTIRE DNA MOLECULE can
Replicate: Then You have 2 from 1 (DNA
REPLICATION---Leads to MITOSIS ..one cell goes
to two cells.
OR
2.
Selected sections of the DNA
strand (genes) can be expressed
(transcribed and into mRNA and Translated into
proteins)
Instructions for the karyotyping homework:
1. Select a SINGLE group member to log into GoogleDocs
2. Make a COPY the Karyotyping homework
3. RENAME: YOUR character_period
4. Share the copy (editing) with your other group
members AND with me
VIDEOS IF TIME
1 What Are Genes? (5 min)
Complementary Base
Pairing
• Nitrogenous bases
united by hydrogen
bonds
• DNA base pairings
– A-T and C-G
• Law of
complementary
base pairing
– one strand
determines base
sequence of other
Segment of DNA
Chromosomes
• A chromosome is one of the threadlike "packages" of
genes and other DNA in the nucleus of a cell.
• Different kinds of organisms have different
numbers of chromosomes.
• Humans have 23 pairs of chromosomes, 46 in all:
44 autosomes and two sex chromosomes.
• Each parent contributes one chromosome to each
pair, so children get half of their chromosomes from
their mothers and half from their fathers.