Bell Work: 1/22/13 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.

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 ) 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 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.  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 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 around proteins. DNA = 2 halves connected in the middle (double helix) Cell is ready to divide= packages chromatin into chromatids. Two identical chromatids=a chromosome ready to divide Before division, human cell=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 DNA Step 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…