1. Science 10 BIOLOGY UNIT
WHAT IS GENETICS?

2. Genetics Genetics is the study of heredity.
Heredity is where a parent passes certain genes to their offspring.
Every child inherits genes from both of their biological parents and these genes in turn express specific traits.
Traits are observable characteristics determined by specific segments of DNA called genes.

3. Examples of Genetic Traits
Freckles,
Hair colour
Curly hair
Dimples
Handedness
Red/green colourblindness

4. Genetic Traits Treasure Hunt

5. What do you remember from Grade 9?
Inside the Nucleus
What do you remember from Grade 9?

6. Label the cell

7. What does the nucleus do?
Directs all of the cell’s activities –
ability to grow, develop and replicate (make copies of itself)
What’s inside the nucleus?
Our genetic information in a long molecule called DNA
Nucleolus
Nucleus directs and control all of the cell’s activities

8. Nucleolus The nucleolus is a round body located inside the nucleus
assembles ribosomal subunits
makes ribosomal RNA (rRNA). It then sends the subunits out to the rest of the cell where they combine into complete ribosomes.

9. How does the nucleus perform it’s job?
Inside the nucleus are the instructions for how to perform all cell activities are carried in molecules of DNA.

10. DNA the book of you Ted Ed video
Ameoba Sisters DNA

11. What is DNA?
DNA stands for Deoxyribonucleic acid
Contains our genetic material - the stuff that determines all our inherited traits;
controls the production of proteins
DNA is found tightly packed in nucleus as chromatin
chromatin condenses to visible chromosomes when a cell is ready to divide
There is an exact copy of DNA in almost every cell
DNA stores instructions for how to form cells, for the chemicals and structure that cells must make and for everything that the cell does

12. DNA Structure
DNA exists as a double helix, a long, two stranded molecule like a twisted ladder.
Twisted ladder

13. How was the structure of DNA discovered?
In the early 1950s two scientists, Rosalind Franklin and Maurice Wilkins, studied DNA using x-rays.
Franklin produced an x-ray photograph that allowed two other researchers, James Watson and Francis Crick to work out the 3D structure of DNA. The structure of DNA was found to be a Double helix (twisted ladder).
claudio-l-guerra
The human genome contains approximately 3 billion base pairs, and more than 99 percent of those bases are the same in all people.
How does DNA relate to heredity?

14. What is DNA made of? DNA is made of repeating units called nucleotides
Each nucleotide is composed of three parts:
Phosphate group
Sugar (pentose)
Nitrogenous base
The sugar and phosphate make up the “sides” of the ladder

15. Nitrogenous bases
The bases pair up in the middle, forming the “rungs”of the ladder.
Hydrogen bonds between the nitrogenous bases hold the two strands of DNA together. 
The hydrogen bonds are base specific. A can only bind with T. and C binds with G

16. Nitrogenous Bases
There are four different nucleotides because there are four different bases:
adenine (A),
guanine (G),
cytosine (C),
thymine (T)
two types of bases:
purines – A, G have a double ring structure
pyrimidines – C, T, have a single ring structure

17. Complementary Base Pairing:
A with T
C with G
Chargaffs Rule:
the amount of A = T, C = G
Apples in the tree
Cars in the Garage

18. What part of DNA makes up our genetic code?
It is the sequence of these bases that determines our genetic code.
Our genetic code determines
what proteins are produced and
What traits we have

19. Genes
They are basic units of heredity: determine our traits and protein production
Genes are segments of DNA that code for a particular protein.
Genes vary in size from a few hundred DNA bases to more than 2 million bases
Humans have about 23,000 genes
Video Stated Clearly: What is a gene?
Genes – segments of DNA, DNA tightly coiled as chromatin, condenses into chromosomes.
Do you think the more sophisticated the organism, the more genes?
Human Geneome Project: About the same as a chicken or a nematode
Less than corn

20. Genes
Genes always occur in pairs: Because we have 2 sets of chromosomes (one from mom, one from dad),
Alleles are forms of the same gene with small differences in their sequence of DNA bases.
How can each cell have the same copy of DNA?

21. Putting it all together
Genes are segments of DNA.
DNA exists as a long molecule tightly coiled into chromosomes.
Chromosomes are found in the nucleus of every cell.

22. How many chromosomes do we have?
Humans have 23 pairs of chromosomes (haploid number) for a total of 46 (diploid number).
22 of these pairs are autosomes,
23rd pair, the sex chromosome
Females have XX
Males have XY
Karyotype
Does number of chromosomes indicate how evolutionary advanced we are?
Remember DNA is tightly coiled into chromatin in the nucleus. Before a cell divides, chromatin condenses to visible chromosomes.
Chromosomes are coiled strands of DNA.
sections of these strands are genes – a sequence of bases that code for a trait/protein.

23. Sex Determination: More Complicated than you thought
Ted Ed video
than-you-thought

24. Build your own DNA
HW: WB p58-60 DNA Worksheet

25. Do all cells have DNA?

26. How does DNA get into new cells?
When cells divide, every new cell needs a copy of the DNA to carry the instructions of how to be a cell. DNA replicates (copies) itself right before a cell divides. Ameoba Sisters DNA Replication :

27. How can each cell have the same copy of DNA?
DNA REPLICATION: the process by which DNA copies itself before a cell divides
DNA Replication is Semi-Conservative:
Each new piece of DNA is made up of 1 old strand and 1 new strand.
This ensures accurate replication.

28. DNA Replication DNA helix unwinds
Complementary nucleotides attach, elongating each strand
Result is two new DNA molecules identical to the original, each with one new strand and one old.
Remember it is the sequence of bases is the code that determines the trait or protein.

29. The sequence of bases that determines the trait or protein.
Who knows how this is done?
3 bases make a codon

30. What is the importance of proteins?
Proteins are made up of smaller building blocks called amino acids, joined together in chains. 
Proteins are molecules that all the cells of the body need in order to work properly.
They determine the characteristics of the organism.
Some proteins are parts of cell structures (collagen, keratin, elastin)
Some drive chemical reactions within the body (enzymes)
Some are messengers (hormones).
Some are in our blood (hemoglobin, antibodies, clotting factors)
Humans have as many as proteins.

31. Where are proteins made?
Proteins are made in the cytoplasm of the cell by ribosomes.
Ribosomes are made in the nucleolus and then move to the cytoplasm.

32. How does the genetic code become protein? (How is a gene expressed?)
Gene Expression: DNA Transcription and Translation

33. Gene Expression
Gene expression is the translation of genetic code into the production of a protein
occurs in processes: Transcription (in nucleus) and Translation (outside nucleus)
Label the diagram
With so many base pairs replicating, the potential for a mismatch is common.
Transcription and translation video 5 min:

34. From genetic code to protein
DNA remains in the nucleus but proteins are made in the cytoplasm of the cell.
How does the code get to the ribosomes where the protein is made?
The message must be copied and carried out of the nucleus.
RNA is the messenger

35. RNA RNA is ribonucleic acid
Like DNA, it is also a strand of nucleic acids except:
it is single-stranded,
instead of thymine it uses Uracil to pair with adenine.
It’s sugar is ribose instead of deoxyribose
mRNA is called messenger RNA because it takes the copied message out to the ribosomes to make protein.

36. Difference between RNA and DNA
STRUCTURE:
DNA
RNA
Strands of nucleotides
Double
Single
Sugars
Deoxyribose
Ribose
Nitrogen Bases
Thymine
Uracil

37. Video Amoeba Sisters RNA
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38. Video Amoeba Sisters Protein Synthesis