DNA and Genome

Multiple Choice

How many sets of chromosomes do gametes have?

• ONE

• TWO

• THREE

Multiple Choice

Where are gametes produced?

• In all body cells

• in reproductive cells

• In skin cells

Multiple Choice

How many cell divisions occur in meiosis?

• One

• Three

• Two

Multiple Choice

How many daughter cells does meiosis produce?

• Two

• Three

• Four

Multiple Choice

Gametes are all genetically identical.

• True

• False

Multiple Choice

Following fertilization, how does the resulting cell grow?

• Meiosis

• Mitosis

• Specialization

Poll

Are you ready to learn something new today?

• Yes

• No

• Maybe

• I am not sure

—B.B. King

“Education is the most powerful weapon you can use to change the world.”

DNA and the GENOME

​Lesson Objectives

• To state that DNA contains a code to build proteins.

• To describe the relationship between DNA, genes, and chromosomes and describe some of the benefits of studying the human genome.

• To explain why knowledge of the genomes of other species is useful.

DNA

• Inside the nuclei of cells, chromosomes are made up of long molecules of DNA.

• DNA stands for deoxyribonucleic acid – it is the chemical that all of out genetic material is made of.

• DNA is a polymer – a large molecule built from a chain of smaller molecules.

• These long strands of DNA twist and spiral to form a double helix structure.

• If you were to take all of the DNA in a single cell and unravel it into a single strand, it would be 2m in length – this is why it is split across 46 chromosomes.

Structure of DNA

Nucleotide and Bases

• DNA strands are polymers made up of many repeating units called nucleotides.

• Each nucleotide consists of a sugar, a phosphate group and a base

• There are four types of bases – A, C, G, and T. Each sugar joins to a base.

• The sugars and phosphate groups form a ‘backbone’ to the DNA strands.

• It is the order of bases in a gene that decides the amino acids in a protein.

• Each amino acid is coded for by a sequence of three bases in the gene, and the amino acids join to form proteins.

• Each base in a DNA strand links to a base on the opposite strand in the helix. A base will only pair up with its complimentary pair:

•A and T / T and A

•C and G / G and C

​

​Complimentary Base Pair

Gene

• A gene is a small section of DNA found on a chromosome.

• Each gene codes for a particular sequence of amino acids which are put together to make a specific protein.

• Only 20 amino acids are used, but they make up thousands of different proteins.

• Genes simply give the instructions for the sequence of amino acids that need to be put together.

Gene

Eyes upfront...Pay attention to the video!!

Multiple Choice

What is the meaning of DNA?

• Daddy Not Available

• Deoxyribonucleic Acid

• Dioxyribonucleic acid

Multiple Choice

What shape does the DNA have?

• single helix

• Double helix

• Triple helix

Multiple Choice

What is the nucleotide made of?

• sugar, base and phosphate

• flour, stage and phosphate

• Rice, base and phosphate

Poll

What are the complimentary pairs?

• A, G, T, C

• A, B, G, T

• G, U, C, B

​Human Genome Project

• Genome à the entire set of genetic material in an organism

• This includes all of the chromosomes and the genetic material found in the mitochondria as well.

• Mitochondria have their own DNA that is always inherited from the mother because it comes from the mitochondria in the egg.

• The human genome contains over 3 billion base pairs and almost 21,000 genes that code for proteins.

​Human Genome Project

• The Human Genome Project started in 1990 and was completed in 2003.

• Scientists from different universities across the world collaborated to determine the sequence of base pairs that made up the genome of a random man and women.

• Since the initial human genome was read, scientists have carried on with their work – they are currently busy with the 100,000 genomes project. The overall aim is to find out as much as possible about human DNA.

​Why does Genome matter?

• Understanding the genome has taken years and comes at a considerable financial cost, however the effort is deemed worthwhile in facilitating:

• Understanding the genome helps us to understand inherited disorders such as cystic fibrosis and sickle cell disease.

• Furthering the search to linking genes to different types of disease such as Type 2 diabetes.

• Analysis of genomes of cancer cells to select the best treatment for individuals.

• Understanding evolution and history, such as migration patterns.

Multiple Choice

What is the genome of an organism?

• I am not sure

• The entire genetic material

• The entire cell make up

Multiple Choice

The project also looked at DNA in the mitochondria.

• True

• False

Multiple Choice

The project found that the human genome contains over 3 billion base pairs.

• True

• False

Multiple Choice

The project found that the human genome contains over 21,000 genes.

• True

• False

Multiple Choice

The Human Genome Project was completed in 2001.

• True

• False

Multiple Choice

The Human Genome Project was completed by UK scientists.

• True

• False

Poll

Did you learn something new today?

• Yes

• No

• I think

• Maybe