PNP WK6

Question 1

What are chromosomes?

Answer 1

• made up of thousands of genes (segments of DNA that contain info about how to synthesise a protein)
• Body contains 23 pairs chromosomes, 22 pairs are autosomes and one pair is sex chromosomes

Question 2

What is the difference between autosomal and X-linked inheritance?

Answer 2

Autosome: gene being expressed is located on an autosome
X linked: gene being expressed is located on the x chromosome

Question 3

What is ploidy?

Answer 3

Number of sets of chromosomes in an organism, aneuploidy is abnormal no. of sets

Question 4

What is a codon?

Answer 4

A sequence of 3 DNA/RNA nucleotides that correspond to a specific amino acid during protein synthesis

Question 5

What is a point mutation?

Answer 5

replacement of a single base pair with another that can change the identity of an amino acid, create a stop codon, or create a new start codon

Question 6

What changes can come from a point mutation?

Answer 6

• Turn off a gene so there is no protein
• Stop transcription early and producing a dysfunctional protein
• Prolong transcription so protein cannot function
• Increase function of a protein
• Create interfering protein with normal protein

Question 7

What are chromosomal disorders?

Answer 7

• Error during meiosis where chromosomes swap portions
• Can cause a translocation (abnormal placement part of chromosome)
• Can cause an altered structure (deletion)

Question 8

What are multifactorial disorders?

Answer 8

• Polygenic or teratogen exposure
• Caused by environmental factors
• Breast cancer or schizophrenia

Question 9

What is somatic v gamete gene therapy?

Answer 9

Somatic: normal gene is inserted into somatic cells, cannot be passed on
Gamete: gene is passed on to the children of the person with a hereditary disease as a result of manipulation of the sex

Question 10

What is organogenesis?

Answer 10

when differentiation and development of the organs are taking place

Question 11

What is a teratogen?

Answer 11

a chemical, physical, or biological agent that produces abnormalities during embryonic or fetal development.

Question 12

What are the different routes of action for teratogens?

Answer 12

• Direct exposure to agent
• Through pregnancy exposure (takes a while)
• As a result of mutagenic effects of a teratogenic agent that occurs before pregnancy

Question 13

Describe the development of the heart for an embryo

Answer 13

• First to form and develop
• Begins pumping blood on day 21/22
• Develops from cardiogenic area
• Made from cardiogenic cords that form single hollow tube
• Internal septa forms day 28
• AV and semilunar valves develop wk 5-9

Question 14

Describe the development of the respiratory system for an embryo

Answer 14

• Begins 4 wks into gestation
• Endothermal tissue will form laryngotracheal bud, and trachea will develop proximally
• Alveolar ducts with type I cells, surfectant is produced
• Completed by 36 wks

Question 15

Describe the development of the renal system for an embryo

Answer 15

• Pronephros, non functional stage
• Mesonephros, transitional kidney formed
• metanephros, development continues until wk 10
• Nephrogenesis, development of ureteric buds, which develop into the ureter, pelvises, calyces, and collecting ducts until wks 32-36

Question 16

Describe the development of the GI system for an embryo

Answer 16

• Foregut develops: The pharynx, oesophagus, stomach, liver, gall bladder, pancreas and part of the duodenum
• Midgut develops: duodenum, jejunum, ileum, ascending colon, and two-thirds of the transverse colon
• Hindgut develops: one-third of the transverse colon, the descending colon, the rectum, and the urogenital sinus.

Question 17

What is cellular senescence?

Answer 17

• state of irreversible growth arrest, meaning that cells lose their ability to divide
• triggered by DNA damage (chemicals, mutation errors, reactive oxygen species
  (-oxides)
• triggered by telomere shortening

Question 18

How does aging affect neuromuscular and cardiac function?

Answer 18

Neuro: loss of neurons and neural dendrite atrophy, declined motor strength and reflexes
Cardiac: Increased stiffness in blood vessels, decreased HR and diastolic ventricular relaxation

Question 19

How does aging affect immune and integumentary function?

Answer 19

Immune: altered. diminished T helper cell function
Integ: thin dry skin, decreased sebum production, thick nails

Question 19

How does aging affect respiratory and GI function?

Answer 19

Resp: decreased VO2max and elasticity in lungs
GI: Mucosal atrophy, constipation, dry mouth

Question 20

How does aging affect renal and genitourinary function?

Answer 20

Renal: Glomeruli function decreased, decline in renal blood flow
Genit: Decreased bladder capacity, decreased testosterone in men and increased dryness in women

Question 21

How is absorption of drugs affected by age?

Answer 21

• in the newborn infant; low levels of bile may lead to impaired absorption and reduced bioavailability of drugs
• In the adult, penicillin is poorly absorbed from the gut because it is degraded by stomach acid
• Slowed peristalsis and gastric emptying can lead to higher plasma drug levels than expected.

Question 22

How is the distribution of drugs affected by age?

Answer 22

• concentration of plasma proteins is lower in the very young and the very old, leading to a higher proportion of unbound drugs in blood
• Drug activity and potential toxicity is increased, even though total drug concentration in the plasma is within the expected range.
• neonates, there will be a lower concentration of drug around its specific receptors and a diminished response
• in older people there will be a higher-than-expected drug concentration with greater effects due to ECF present

Question 23

How is the metabolism of drugs affected by age?

Answer 23

• Neonates have a greater capacity to metabolise certain medications due to hepatic abilities
• In children the liver is much larger, therefore able to metabolise quicker
• In adults ability to metabolise deteriorates