SNC2D Genes

Did you know? The source of smelly feet, like smelly armpits, is sweat. And people sweat buckets from their feet. A pair of feet have 500,000 sweat glands and can produce more than a pint of sweat a day.smelly feetsweat

PKU? PKU = phenylketonuria –A genetic condition –If not caught early by genetic screening, could lead to severe brain damage –Can be corrected by increasing intake of a specific protein –knowledge and understanding of the cell has led to discovering what causes this disease

Activity Time! Get into groups of 4 Letter off your group members from A-D Each person will be responsible for taking notes on a topic and then your topic to the rest of the group – make it simple and easy to understand (use examples, analogies, etc.) **ALL GROUP MEMBERS SHOULD HAVE NOTES ON ALL TOPICS Let’s practice – look to p10, how can we summarize? –A – DNA Screening p19 –B – Drug Research p22 –C – Transgenic Organisms p23 –D – Cloning p24-25

Where is the Genetic Information? Nucleus –Genetic information (DNA) carried in structures called chromosomes –Genetic information = Instructions for… What each cell will become How the cell will function How long the cell will live before it divides

Well, duh!

DNA = Instructions

Let’s learn about DNA! Short videovideo

Multicellular Organisms Humans have 46 chromosomes in each somatic (body) cell (except the gametes = ovum/sperm, which have 23) Different species may have different numbers of chromosomes Horse  64 Cat  38 Dog  78 Pea  14 Rice  24 Apple  34

DNA: the Code Each chromosome is made up of a single molecule of DNA DNA is divided into segments called genes Genes provide instructions for making proteins, which control the cell’s activities How can such a long molecule be stored in a small space? Check this out!this

Draw this!

DNA Structure DNA appears as a twisted ladder that is called a double helix (two strands of DNA twisted around an axis) Each “rung” of the ladder is a building block of the molecule When the building blocks are strung together, a molecule of DNA forms – like this!this!

DNA Structure Made up of 4 types of building blocks (like Lego!) that are represented by letters: –A (for adenine) –T (for thymine) –C (for cytosine) –G (for guanine)

Food for thought.. (don’t write) How do we communicate to each other? What does each of the following mean? –kobo –meti –etwar But what happens when I rearrange the letters? –book –time –water

DNA Structure The order in which A, T, C, and G are put together is called the genetic code Genetic code is different for every person! The code is a message that tells the cell how to make specific proteins (like a factory!) that helps an organism function

Proteins everywhere!

DNA Structure (continued) Base pairs are joined by hydrogen bonds according to the following rules: 1. A pairs up with T 2. G pairs up with C You better know your base pairing rules!

Why is DNA important? DNA contains thousands of genes that controls many of your features How many letters? 6 billion! Can you think of any features determined by DNA? –Hair colour –Eye colour –Height –Whether you can digest milk!

Try this! If you have the sequence of one DNA strand, you can determine the sequence of the other DNA strand. For example: Sequence of First Strand of DNA Sequence of Second Strand of DNA ACGTAGCGGG CCTAGGCTATCCGA

Mutations Changes in the DNA of an organism Caused by mutagens like UV rays, radiation, and harsh chemicals like mercury

Are they all bad?

DNA Screening DNA Screening is the process of testing individuals to determine whether they have the gene or genes associated with certain genetic disorders (i.e. cancer, cystic fibrosis, and spina bifida) Two ways: 1. amniocentesis – fluid is taken from the amniotic sac that surrounds the growing fetus  e.g. test for PKU

DNA Screening 2. We can test for diseases like Down Syndrome with karyotypes

Altering Genes Genetic engineering - combine genes from different species GMO’s – genetically modified organisms or transgenic organisms Benefits? Read p 23 and make a list!

Cloning Cloning – the process of creating identical genetic copies of an organism Why? –Address organ shortage –Agriculture – feed the growing population!

Homework Do “Learning Check” #1-4 p18, #5,6 p22 Make a list of the benefits of GMOs  p 23 Do #6,8 on p28 Tomorrow? Read p22  answer #4 p28 DO YOUR HOMEWO RK! Or else…