1. Knowledge
is knowing
A tomato is a fruit.
Wisdom is not putting
It in a fruit
Salad.

2. DNA DNA is the control center of cellular activity
Only the portion needed for protein synthesis is active in a cell.
Types of DNA:
DNA

3. RNA Three types of RNA: mRNA = messenger – carries instructions
tRNA = transfer – carries amino acids
rRNA = ribosome – puts the other two together to make a protein
This is the working portion of DNA – making the proteins required by this particular cell.
RNA

4. Nitrogenous Bases: Pyrimidine Bases:
Thymine - T- (in RNA this is replaced with Uracil)
Cytosine - C
Purine Bases:
Adenine - A
Guanine - G
Purines are paired with Pyrimidine's and are stable due to hydrogen bonds
A to T in RNA – A to U
G to C
Nitrogenous Bases:

5. A. Nucleotides are built from a phosphate, a sugar, and a base
A. Nucleotides are built from a phosphate, a sugar, and a base. Two different depictions of each base are shown.
B. These parts can be assembled into DNA nucleotides, RNA nucleotides, or adenosine triphosphate.
Question: Which nucleotide contains more phosphate groups – the adenine nucleotide or ATP?
Answer: ATP
Notes:
Nucleotide: organic molecule formed of a simple sugar, a base, and one or more phosphate groups
Builds nucleic acids
DNA builds protein
RNA is a messenger for DNA and has its own functions
Adenosine triphosphate (ATP) transfers energy
Creating ATP adds to energy reserves
Breaking down ATP releases energy when needed
Nucleotides

6. A. Nucleotides found in DNA or RNA can encode information.
B. Nucleotides such as ATP store energy in high-energy bonds.
Question: Name the base found in ATP.
Answer: Adenine
Nucleotide Function

7. Transcription DNA never leaves the nucleus.
A messenger RNA copy of the gene is sent out to the cytoplasm.
Transcription

8. RNA
Transfer RNA
Ribosomal RNA
Messenger RNA

9. Replicating DNA Helix Mitosis -

10. Daughter cells are EXACTLY the same as the original cell
Mitosis

11. Which type of RNA moves from the nucleus into the cytoplasm, carrying the genetic code?
Messenger RNA (mRNA)
Transfer RNA (tRNA)
Ribosomal RNA (rRNA)
All of the above can move between the nucleus and the cytoplasm.
Question

12. Mutations occur due to ERRORS in the duplication process of the DNA.
Substitution – base pair is replaced
Loss/addition – base pair is lost or a new set is added - the strand shortens or lengthens as needed
Rearrangement – base pairs trade places
Cell function – protein synthesis is impacted whenever mutations occur.
Mutations

14. Telomeres Telomeres: DNA sequences at the ends of the chromosomes
Telomere shortens with each division
The end of the telomere does not get duplicated
What will happen to the telomere as the cell continues dividing?
When telomere is gone apoptosis occurs
A man has a mutation that causes some of his cells to rebuild their telomeres after every division; is this a good thing or a bad thing? Why?
Telomeres

15. Tell whether the following statement is true or false: A- true B- false
Mitosis results in the formation of gametes (reproductive cells).
Question

16. Meiosis Genetic content is located on Chromosomes IN MEIOSIS:
Chromosomes duplicate
One pair goes to each daughter cell on the first division
One chromosome of each pair goes to the daughter cell on the second division
Produces daughter cells (gametes) with only one copy of each chromosome
Meiosis

17. 2n = 23 pair (46 total chromosomes)
1n = 23 total chromosomes – no pairs
With fertilization the chromosomes in the egg combine with the sperm and make 23 pair.

18. Chromosomes Chromosomes carry genetic information
They are arranged in pairs – one from mom and one from dad
22 pairs are AUTOSOMES – same in males/females
23rd pair are called SEX CHROMOSOMES.
These determine sex of child
Females = XX
Males = XY
Chromosomes

19. “Family members of the late Keith David Thompson and his widow, Wilda, are missing a normal, cancer-suppressing P53 gene. That condition raises the risk of cancer to about 90%.” Keith and five of his six children have had cancer (five died). Fourteen of their grandchildren have the gene, six have had cancer, three died.

20. Karyotype

21. GENE Each chromosome is divided into bands which we call genes:
Inherited characteristics are found in gene pairs.
GENE

22. Genotype The karyotype contains a persons GENOTYPE-
Genetic information!
Genotype

23. What the genes manifest – what you ‘see’ is the PHENOTYPE

24. Expressivity – how strongly a gene is expressed
Locus – where the gene is located on the chromosome
Alleles – alternative forms of a gene at the same locus
Polygenic – multiple genes from different loci influence a trait
Most human traits are polygenic
These can be predictable but not nearly as easily as single-gene traits.

25. Alleles can be DOMINANT or RECESSIVE:
Dominant = child needs only one to be expressed
Designated as a CAPITAL LETTER
Recessive = child must have two to be expressed
Designated as a LOWER CASE letter
Carrier = an individual who has a recessive gene (which is not expressed)
In SICKLE CELL ANEMIA carriers are immune to malaria.

26. HOMOZYGOTE = the same type of allele – either dominant or recessive.
HETEROZYGOTE = one dominant and one recessive
CO-DOMINANCE = both alleles are expressed
POLYMORPHISM = more than one normal allele at the same locus
Blood groups fall into the category of both polymorphism and co-dominance

27. Which of the following statements is true about an individual who is a carrier for the cystic fibrosis (CF) gene?
Homozygous; suffers from CF
Homozygous; does not suffer from CF
Heterozygous; suffers from CF
Heterozygous; does not suffer from CF
Question

28. If you have the allele for a trait, do you display the trait?
No: It is recessive
Yes: It is dominant
Discussion:

29. Punnett Square Summarizes Genetic Inheritance Process

30. Punnett Square: Single-Gene Autosomal
Mom’s alleles
Dad’s alleles b bb B Bb
Punnett Square: Single-Gene Autosomal

31. Genetic/congenital disorders
Birth Defects: abnormalities of
Body structure
Function
Metabolism
Present at birth
Leading cause of infant death
Due to:
Genetic mutations
Environmental factors
Genetic/congenital disorders

32. Genetic/chromosomal Can be due to changes (MUTATIONS) IN DNA
Or CHROMOSOMAL REARRANGEMENTS
ABNORMAL NUMBER of chromosomes
SINGLE – GENE: single mutant gene
May be autosomal or sex linked
(on X chromosome)
See table 6-1 for a list
Genetic/chromosomal

33. Single-Gene continued
AUTOSOMAL DOMINANT:
Single mutant allele from AFFECTED parent
50% chance of inheriting
AUTOSOMAL RECESSIVE:
Both alleles must be affected
Both parents unaffected (carriers) – SICKLE CELL
Single-Gene continued

34. X-linked Almost always recessive
Females not affected as they have an opposing X gene
Males typically affected as they lack another X
Example – Hemophilia, color blindness
X-linked

35. If an unaffected mother carries one normal and one mutant allele on her X chromosome, what are the chances that she will transmit the defective gene to her sons?
25%
50%
75%
100%
Question

36. Punnett Square: Single-Gene Sex-Linked
Mom’s alleles
Dad’s alleles Xb X Y
Xb Y
X Y XB
Xb XB
X XB
Punnett Square: Single-Gene Sex-Linked

37. Multifactorial disorders
Caused by multiple genes and environmental factors
Cleft lip/palate
Clubfoot
Congenital hip dislocation
Congenital heart disease
Urinary tract malformation
Some appear later in life:
Coronary artery disease
Diabetes mellitus
HTN
Cancers
Mental illnesses
Multifactorial disorders

38. Chromosomal Disorders
Notice that the occurrence increases in women who bear children after the age of 35.
Disorders can be due to ALTERED chromosome structure OR ABNORMAL NUMBER of chromosomes
Chromosomal Disorders

39. Chromosomal Disorders
Altered Structure:
DELETION - loss of a portion of a chromosome
INVERTED – broken portion reattaches not in original manner
TRANSLOCATION – two chromosomes break then reattach on the other.
Chromosomal Disorders

40. Translocation: aka - Crossing-Over
When chromosome pairs line up during meiosis, they can exchange ends
Each of the four resulting gametes will have a different combination of genes
Translocation: aka - Crossing-Over

41. Which type of chromosome alteration generally results in normal offspring?
Deletion
Inversion
Translocation
Ring formation
Question

42. Chromosomal Disorders
Abnormal Numbers:
Chromosomes fail to separate – NONDISJUNCTION
Germ cell has either 22 or 24 chromosomes
Fertilized cell has either 45 or 47 chromosomes
Monosomy
45 chromosomes – usually leads to miscarriage
If only one sex chromosome (X) results in TURNER’S SYNDROME:
Chromosomal Disorders

43. TURNER’S SYNDROME

44. Chromosomal Disorders
Trisomy
47 chromosomes
Trisomy 21 is the most common (Down Syndrome)
Also documented on 13, 18, 22 – usually results in death for the infant.
Chromosomal Disorders

45. Trisomy 21
Down Syndrome -

46. Chromosomal Disorders
Klinefelter syndrome: XXY
Male with an extra X chromosome
Results in testicular dysgenesis
Inability to produce sperm
Voice may not change
Wide variety in manifestations
Chromosomal Disorders

47. Environmental Causes for Congenital Disorders
Scenario:
Mrs. K is a diabetic and is having trouble keeping her blood glucose constant during pregnancy…
She works in a dry-cleaners store next to a gas station and drinks heavily.
She is diagnosed with toxoplasmosis.
Question:
What kinds of stresses is her fetus experiencing?
Environmental Causes for Congenital Disorders

48. Environmental Teratogens
Wide variety of environmental causes of birth defects:
Mom’s general health and hormone balance
Nutrition and Drugs
Diabetes, smoking, alcohol, radiation
Infectious agents
Fetus most vulnerable from day 15 to day 60
Each organ has a development time – fig 6-12
Environmental Teratogens

49. Teratogenic Agents RADIATION Heavy doses of ionizing radiation
CHEMICALS
Mercury found in contaminated fish……
DRUGS
Most cross the placenta
Pregnancy classifications:
A – least dangerous
B,C,D – increasingly more dangerous
X – known/proven teratogens
Teratogenic Agents

50. Teratogenic Agents ALCOHOL – Leads to fetal alcohol syndrome
FREELY crosses placenta
Fetal alcohol levels EQUAL/GREATER than moms
Harmful throughout pregnancy
FOLIC ACID deficiency:
Leads to neural tube defects – spina bifida
INFECTIOUS
TORCH –Toxoplasmosis, other, rubella, cytomegalovirus, herpes
Others: varicella-zoster, Epstein-Barr, syphilis, HIV
Teratogenic Agents

51. Now let’s look at blood