Download 2-5 DNA Cont. and Cell Cycle

Answer the Monday
question on the
bellwork sheet.
Bellwork 2-8-2016
01/25/12
Objectives
Am I able to describe the relationship among genes,
chromosomes, and inherited traits? (0707.4.3)
Am I able to sequence a series of diagrams that depict
chromosomes movement during plant cell division? (0707.1.4)
Students will be able to describe the principal mechanisms by
which living things reproduce and transmit information
between parents and offspring.
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Cells
What is the control center of both the
plant and animal cell?
nucleus
Nucleus
The nucleus is a large organelle in a eukaryotic cell that contains
chromosomes.
What part of the school are the chromosomes like?
Chromosomes are made up of protein and DNA.
The proteins carry out all the functions and characteristics of living
organisms, such as carrying substances, sending messages, &
protecting the body.
DNA, or deoxyribonucleic acid, is genetic material that determines a
plant or an animal's inherited traits.
Genes are sections of DNA that give instructions for inherited traits,
which are passed from one generation to the next.
Traits are the different forms of characteristics, such as purple petals or
brown hair, that plants and animals have.
Relationship among chromosomes,
DNA, & genes...
Nucleus contains
chromosomes
Chromosomes
are made of DNA (&
proteins)
Sections of DNA are called
genes.
Genes are sets of
instructions for inherited
traits
DNA
A strand of DNA
looks like a
twisted ladder.
This shape is known
as a double
helix.
DNA Structure
DNA is made of nucleotides (biological molecule).
A nucleotide consists of a sugar, a phosphate, and
a base.
Four types of nucleotides:
Sides or backbone = phosphate + sugar
Making Copies of DNA
• The pairing of bases allows
the cell to replicate, or make
copies of, DNA.
• Each base always bonds with
only one other base.
• Adenine (A) > Thymine (T)
• Guanine (G) ] Cytosine (C)
The sequence CGAC will
bond with what?
Sequence GCTG
How & When Copies are
Made
• During replication, a
DNA molecule is split
down the middle, where
the bases meet.
• The bases on each side
of the molecule are
used as a pattern for a
new strand.
• DNA is copied every
time a cell divides.
• The job of unwinding,
copying, and re-winding
the DNA is done by the
proteins within a cell.
RNA
RNA, or ribonucleic acid, is another type of
molecule that helps make proteins.
RNA is so similar to DNA that RNA can serve
as a temporary copy of a DNA sequence
called messenger RNA (mRNA).
Proteins are built in the cytoplasm by using
RNA copies of a segment of DNA.
How DNA
Works:
Use pgs. 134-135 to
create a flow chart
that explains how
DNA works.
A cell’s DNA codes for
proteins that determine
traits, like skin color
“Somebody
explain that
one…”
A single strand of
chromatin= DNA
that is coiled around
proteins.
Cell is ready to divide=
packages chromatin
into chromatids.
“Say what!? Why
would DNA coil
around proteins?”
“Copy that…why
would we need to
make copies of our
DNA?”
Two identical
chromatids=a
chromosome ready to
divide
Before division, human
cell=46 chromosomes
(two identical copies of
genetic material)
Changes in Genes
Check out pg. 138 & 140!
Changes in the number, type, or order of bases on
a piece of DNA are known as mutations.
Sometimes bases are left out, extras are added, or
the most common, the wrong base is used.
Consequences of Mutations:
improved trait, no change, harmful trait
Most of the time proteins detect an error and fix it.
Mutagens, like radiation, can cause mutations in
DNA.
When scientists manipulate or change individual
genes within organisms it is called genetic
engineering.
DNA fingerprinting identifies the unique patterns in
an individual’s DNA.
A clone is an exact copy of another organism’s
genes.
Elbow Partner Questions...
Does every cell contain the same DNA?
✔
Every cell in your body has the same
genes, and DNA. Your cells have all
of the genetic information for your
whole body. Your skin cells have the
genetic make up of your skin and
your muscles. Your skin does not use
this extra information.
More Elbow
Questions...
How do things get cloned?
✔
To make Dolly, researchers isolated a somatic cell from
an adult female sheep. Next, they transferred the
nucleus from that cell to an egg cell from which the
nucleus had been removed. After a couple of
chemical tweaks, the egg cell, with its new nucleus,
was behaving just like a freshly fertilized zygote. It
developed into an embryo, which was implanted into
a surrogate mother and carried to term.
✔
The lamb, Dolly, was an exact genetic replica of the
adult female sheep that donated the somatic cell
nucleus to the egg. She was the first-ever mammal to
be cloned from an adult somatic cell.
Mutations
Beneficial Mutations:

✔
Harmful mutations:
✔
✔
wild almond tree seeds “contain an
intensely bitter chemical called
amygdalin, which … breaks down
to yield the poison cyanide.
Occasional individual almond trees
have a mutation in a single gene
that prevents them from making a
poison.
Those non-bitter almond seeds are
the only ones that ancient farmers
would have planted, at first
unintentionally in their garbage
heaps and later intentionally in
their orchards.
More Mutations…
• Red hair appears in
people with two copies
of a recessive gene on
chromosome 16 which
causes a mutation in the
MC1R protein.
• Red hair has far more of
the pigment
pheomelanin than it has
of the dark pigment
eumelanin.
Even more…
Blue eyes are a genetic
mutation affecting the
gene that produces
brown eyes literally
'turns off' the ability to
produce brown eyes.
Rather than completely
turning off the gene,
the action is limited,
which reduces the
production of melanin
in the iris. In effect, a
person will have blue
eyes.
How do little elephants grow up to be BIG
elephants?
58. Cell Cycle
•50,000
of the cells in your body will die and be
replaced with new cells, all while you have
been reading this sentence!
•It takes about 8 hours for one of your cells to
completely copy its DNA.
•One single cell contains two meters of DNA.
The life cycle of a cell is called the
cell cycle. The cell cycle begins
when the cell is formed and ends
when the cell divides and forms
new cells.
Three reasons why cells
reproduce:
Growth
2. Repair
3. Replacement
1.
Skin cancer - the abnormal growth
of skin cells - most often develops
on skin exposed to the sun.
Cells reproduce constantly.
DNA & Chromosomes
Before a cell divides, it must make a
copy of its DNA, or deoxyribonucleic
acid.
 Review: Where is DNA found and what
does it do for the cell?
 DNA is the heredity material that controls
the cells activities, including the making
of new cells.
 The DNA of a cell is organized into
structures called chromosomes.

Chromosomes

Human body cells have
46 chromosomes, or 23
pairs of chromosomes.

These pairs are made up
of similar chromosomes
known as homologous
chromosomes.
Challenge Questions:
 Why does our DNA
compact into these
chromosome structures?
 Why do we have 23 pairs
of chromosomes?
Mitosis
Cell division occurs in a series of stages, or phases.
Look @ pgs. 88-89
• Interphase
• Prophase (Mitosis Phase 1)
• Metaphase (Mitosis Phase 2)
• Anaphase (Mitosis Phase 3)
• Telophase (Mitosis Phase 4)
• Cytokinesis
Mitosis Sequences
With your group, sequence the phases of
mitosis in order using the cards.
At the bottom of your notes, draw your
card sequence and justify why this order
is correct.
http://www.cellsalive.com/mitosis.htm
Good app to use for studying
and making foldable!
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Mitosis Foldable
1. Fold paper in half hot-dog style.
2. Crate six flaps on one side.
3. Label each flap with the names of the
mitosis phases.
4. Using your book or the mitosis app, draw
a picture of each phase of mitosis on
the inside of the flap, and take notes on
the important parts of this phase. This is
homework if you do not finish!
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Interphase
Replication of DNA
Centrosomes, which contain centrioles,
copy.
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Prophase
MITOSIS begins
Chromatin has turned in chormatids
(chromosomes)
Nuclear Membrane disappears
Spindle fiber form between the centrioles
and attach to centromeres.
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Metaphase
Chromatids align at the center of the cell
and are held in place by spindle fibers
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Anaphase
Chromatids separated and are pulled to
opposite ends of the cell.
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Telophase
Two new nuclei form
Chromosomes unwind
MITOSIS is complete
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Cytokinesis
Two daughter cells are created.
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Interphase
Prophase
Metaphase
Anaphase
Telophase
Cytokinesis
IPMATC
I Pray More At The Church
3-2-1 Reflection
3 things you have learned about DNA
and cell division.
2 questions you have about this topic.
1 way you can relate this to the realworld.
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