Bell Work: 1/26/15

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Bell Work 1/26/15

• Based on the figure to the left, which of the
  following statements best describes
  cross-pollination?
• A The stigma comes in contact with flowers from
  another plant.
• B Pollen from the anther travels to the stigma of
  the same flower.
• C Pollen from the anther travels to the ovule of
  a different flower.
• D Wind transfers pollen from other plants,
  delivering it to the stigma.

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Challenge Question

• During pollination, what determines the
  characteristics (type, color, size, etc.) of the
  new flower that will be produced from the seeds?

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Objectives

• Can I describe the relationship between genes,
  chromosomes, and inherited traits? (SPI 0707.4.3)

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Cells

• What is the control center of both the plant and
  animal cell?
• nucleus

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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.

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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
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Brain Pop
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DNA

• A strand of DNA looks like a twisted ladder.
• This shape is known as a double helix.

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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
• Rungs of the ladder pair of bases

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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) gt Thymine (T)
• Guanine (G) Cytosine (C)

The sequence CGAC will bond with what?
Sequence GCTG
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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.

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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.

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How DNA WorksUse pgs. 134-135 to create a flow
chart that explains how DNA works.
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A cells DNA codes for proteins that determine
traits, like skin color
A single strand of chromatin DNA that is
coiled around proteins.
Cell is ready to divide packages chromatin into
chromatids.
Two identical chromatidsa chromosome ready to
divide
Before division, human cell46 chromosomes (two
identical copies of genetic material)
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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 individuals DNA.
• A clone is an exact copy of another organisms
  genes.

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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.

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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.

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Mutations

• Harmful mutations

• Beneficial 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.

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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.

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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.

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DNA Drawing

• Draw a portion of a DNA strand.
• You must show the following
• Double helix structure
• Phosphate sugar backbone
• Paired bases in the middle (must be correctly
  bonded base pairs)

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3-2-1

• 3 things you learned today
• 2 questions you have
• 1 way this relates to your daily life