bell work: 1/22/13 based on the figure to the left, which of the following statements best describes...
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Bell Work: 1/22/13Based 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.
Challenge Question
During pollination, what determines the characteristics (type, color, size, etc.) of the new flower that will be produced from the seeds?
Objectives
Describe the relationship between genes, chromosomes, and inherited traits (SPI 0707.4.3)
Table of Contents: #55.DNA Notes
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
Chromosomesare 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. 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
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.
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
DNA is part of a material called
chromatin, which is bundled in the nucleus.
A single strand of chromatin= DNA
that is coiled aroundproteins.
DNA = 2 halvesconnected in the
middle (double helix)
Cell is ready to divide=packages chromatin
into chromatids.
Two identical chromatids=a
chromosome ready to divide
Before division, humancell=46 chromosomes(two identical copies of
genetic material)
3-2-1 3 things you learned today…
2 questions you have…
1 way this relates to your daily life…
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.
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)
Paper DNAStep 1: label the bases on the paper model with A, T, G, or C from the bottom to the top. Color code the boxes lightly with colored pencil, using the DNA guide on the board.
Step 2: “Unzip” the paper model by cutting it in half vertically and glue the pieces in the correct location on your worksheet so the bases match up correctly.
Step 4: Have me check your work & build a DNA model!
Step 3: Label the empty boxes using A, T, G, or C and then color them using the colors on your DNA Guide (see below). Remember to match the bases correctly!
A – T
T – A
G – C
C - G
3-2-1 3 things you learned today…
2 questions you have…
1 way this relates to your daily life…