Histology

Question 1

3 types of lipids prevalent in the plasma membrane

Answer 1

1. Phospholipids - hydrophilic heads, hydrophobic tails (face inner surface of cell)
2. Glycolipids - Lipids attached to a sugar side chain
3. Cholesterol (found only in eukaryotic cells) - maintain cell membrane fluidity and integrity
   - core of cholesterol is acetyl CoA
   - Need NADPH (pentophosphate shunt)
   - serve as precursor for steroid hormones

Question 2

Normal cholesterol value:

Total cholesterol
Triglycerides
LDL
HDL

Answer 2

Total cholesterol: less than 200
Triglycerides: less than 150
LDL: less than 130
HDL: 40 or higher

Question 3

Integral vs peripheral protein

Answer 3

Integral proteins: span the plasma membranes and serve the following roles
1. structural: interacts with cholesterol to maintain structure
2. receptors: bind to small molecules, proteins, enzymes for cell communication. may serve as enzymes themselves
3. Channels: act as passive tranpsorters or active pumps that move ions down or against their concentration gradients respectively

Peripheral protein: attach to the outer surface of the plasma membrane and serve as hormone receptors and cell surface markers (antigens)

Question 4

Carbohydrates

Answer 4

covalently attached to other structures (lipids and proteins) embedded with the plasma membrane
- Glycolipids and glycoproteins are generally located on the outer surface

Question 5

Glycocalyx

Answer 5

refers to all sugar components (glycolipids and glycoproteins) on the external surface of te cell
- these sugar moieties aid in protection, adhesion and absorption

Question 6

Nucleus

Answer 6

house genetic info of the cell
- serves as the location for DNA replication and mRNA and tRNA transcription

Question 7

Nucleolus

Answer 7

contains dense chromatin and protein machinery necessary for the production of rRNA (central chromosome of ribosome)

Question 8

RNA

Answer 8

3 types of RNA (tRNA, mRNA, rRNA) are transcribed from DNA within the nucleus
- rRNA = produced in the nucleolus and combines with proteins to form ribosomes. Structural ribosomal proteins are produced in the cell cytosol and then enter the nucleus via nuclear pores. Once the ribosome is assembled, it is transported back into the cytosol to aid in protein translation
- tRNA responsible for transferring AA to a growing peptide chain during translation
- mRNA serves as a template for an AA sequence of a unique protein

Question 9

Transcription

Answer 9

DNA to mRNA

Question 10

Translation

Answer 10

mRNA to protein

Question 11

Binuclear cells

Answer 11

hepatocytes, cardiac muscle, epithelial cells of urinary tract

Question 12

Multinuclear cells

Answer 12

osteoclasts and skeletal muscles

Question 13

anuclear cells

Answer 13

RBC is the ONLY cell that are anuclear