MCAT biology

Nucleoid Region

DNA region in prokaryotes

Nucleolus (function & location)

Makes ribosomes. Sits in nucleus, no membrane.

Peroxisomes function?

Collect and break down material

Rough ER function?

Accept mRNA to make proteins.

Smooth ER function?

Smooth ER

Golgi Apparatus (function & what it’s specific to)

Modify / distribute proteins. Only in eukaryotes.

COPI vs COPII

COPII → forward

COPI → return

Centrioles (structure and function)

9 groups of microtubules, pull chromosomes apart.

Lysosomes (functions and properties)

Demo & Recycling center. Made by Golgi. Single membrane.

Plasmids (function & what it’s specific to)

In prokaryotes. Carry DNA not necessary for survival.

What are the 3 cytoskeletal proteins found in eukaryotes?

Obligate Aerobe vs Obligate Aerobe

• Obligate Aerobe: Requires O2.

• Obligate Anaerobe: Dies in O2.

Facultative Anaerobe vs Aerotolerant Anaerobe

• Facultative Anaerobe: Toggle between Aerobic / Anaerobic.

• Aerotolerant Anaerobe: Does not use O2 but tolerates it.

Gram+ vs Gram - bacteria

• Gram + is PURPLE, THICK peptidoglycan/lipoteichoic acid cell wall.

• Gram – is PINK-RED, THIN peptidoglycan cell wall & an outer membrane.

Eukaryote vs. Prokaryote

Prions

Infectious proteins. Trigger misfolding. a-helical → b-pleated sheets. Decreased Solubility.

Types of Bacterial Genetic Recombination (hint: 3 Ts 1C)

What are the 3 shapes of bacteria?

Positive sense vs negative sense viruses

If Single Strand:

• Positive Sense: Can be translated by host cell.

• Negative Sense: RNA replicase must synthesize a complimentary strand, which can then be translated.

Viral Genome

May be DNA or RNA. Single or double stranded.

Retrovirus mode of action

Single stranded RNA. Reverse transcriptase needed to make DNA.

Bacteriophage mode of action

Lytic: Virions made until cell lyses.

Viral lifecycle

Lysogenic: Virus integrates into genome as provirus or prophage. Goes dormant until stress activates it.

Cell cycle

What signals cell cycle progression?

1) CDK + Cyclin create a complex

2) Phosphorylate Rb to Rb + P

3) Rb changes shape, releases E2F

What halts cell cycle progression?

1) CDK inhibitors block phosphorylation of Rb

2) So, E2F stays attached

3) Cell cycle halts

Bulbourethral Glands function?

Makes viscous fluid to clean out urethra.

Seminal Vesicles & Prostate Gland function?

Make alkaline fluid to help sperm survive acidic environment of female reproductive tract.

Sperm pathway

Mitosis

Meiosis

FSH in males and females

Males: Triggers spermatogenesis, stimulates Sertoli Cells.

Females: Stimulates development of ovarian follicles.

LH in males and females

Males: Causes interstitial (leydig) cells to make testosterone.

Females: Induces ovulation.

The Menstrual Cycle

Embryogenesis and Development steps

1. Fertilization

2. Morula

3. Blastula

4. Gastrulation

5. Neurulation

Fertilization steps

• Occurs in the Ampulla of fallopian tube.

• Sperm’s Acrosomal enzymes penetrate corona radiate & zona pellucia.

• Acrosomal enzymes inject pronucleus.

• Cortical reaction releases Ca2+ which depolarizes ovum membrane and makes it impenetrable.

Features of morula

Early. Solid mass of cells

Features of Blastula

• Implants in endometrial lining

• Fluid filled blastocoel

• Trophoblast → Chorion / placenta

• Inner Cell Mass → Organism

What does the Ecto, meso, and endoderm differentiate into?

Neurulation process and results

Stem Cells types

Fetal Circulation

2 types of genetic twins

Fraternal = dizygotic

Identical = monozygotic

Determination vs differentiation

Determination: Cell commits to becoming a certain type of cell

Differentiation: Follows determination. Selectively transcribe genes appropriate for cell’s specific function

What are the 3 Fetal Shunts?

Skip Lungs:

• Foramen ovule: R atrium → L atrium

• Ductus Arteriosus: Pulmonary artery ® Aorta

Skip Liver:

• Umbilical vein → inferior vena cava

Temporal vs spatial summation

Temporal: Same space / Different time

Spatial: Different space / Same time

Neurotransmitter removed from synaptic cleft via…

• Breakdown by enzymes

• Reuptake

• Diffusion out of cleft

Types of glial cells and function?

Astrocytes: Blood-brain barrier. Controls solutes moving from bloodstream → nervous tissue.

Ependymal Cells: The barrier between cerebrospinal fluid and interstitial fluid of the CNS.

Microglia: Digest waste in CNS.

Schwann Cells: PNS, makes myelin.

Oligodendrocytes: CNS, makes myelin.

What are the essential amino acids?

PVT TIM HiLL (i doesn’t stand for anything and one L is lysine)

Where is white and grey matter located in the brain and spinal cord?

Brain: White deep / Grey outer

Spinal Cord: Grey deep / White outer

Monosynaptic vs polysynaptic reflex arcs

Monosynaptic: Sensory neuron → motor neuron Polysynaptic: Sensory → interneuron → motor

The central nervous system is composed of?

Brain & spinal cord

PNS is made of?

Somatic and autonomic nervous systems

• Somatic = voluntary

• Autonomic = non-voluntary

What are the 2 divisions of the autonomic nervous system? Functions?

Properties of peptide hormones

Properties of steroid hormones

Properties of Amino Acid-Derivative Hormones

Share traits from both peptide & steroid hormones

• Ex: Catecholamines use GPCR, Thyroxine bind intracellularly

How does a GPCR work?

Direct vs. Tropic Hormones

Direct Hormones: Act directly on target tissue/organ. Ex: Insulin.

Tropic Hormones: Require an intermediary. They only affect other endocrine tissues. Ex: GnRH and LH are both tropic.

Type 1 vs 2 diabetes

Type 1: No insulin, so glucose is not able to enter cells.

Type 2: Desensitized insulin receptors. Glucose unable to enter cells.

Hypothalamic hormones and their functions?

Pancreatic hormones and their functions?

Gonadal hormones M & F

Testosterone in Testes

Estrogen / Progesterone in ovaries

Where does melatonin come from? Function?

Pineal gland: Melatonin controls circadian rhythm

Hormones in the anterior pituitary and functions

What are the hormones in the thyroid gland and function?

Parathyroid gland hormone and function?

Posterior pituitary hormones and functions?

Adrenal cortex hormones and function?

Adrenal medulla hormones and function?

Air Pathway

Explain each component on the spirometer

Inhalation process

Exhalation process

Bicarbonate Buffer (what happens if pH is high or low?)

Protection present in the air pathway (for pathogens)

Blood Pathway

Electrical Conduction pathway in the heart

What is systole and diastole?

Normal BP (systole/diastole). How is it maintained?

What happens during high BP? (how is it regulated?)

ANP: lowers blood pressure and promotes fluid loss (Diuresis)

What happens during low BP? (how is it regulated?)

Fluid retention (vasocontriction)

What happens during high osmolarity? (how is it regulated?)

ADH: Promotes water reabsorption

Cardiac output formula

Cardiac Output = Heart Rate x Stroke Volume.

• CO = HR × SV

Blood types and traits

Coagulation process

Prothrombin → Thrombin

Fibrinogen → Fibrin (mediated by Thrombin)

Plasmin function?

Breaks blood clots

Blood cell types

Hydrostatic Pressure

Moves fluid out of the blood vessel and into the interstitial fluid around it.

Osmotic Pressure

“Sucking” pressure generated by solutes as they draw H2O into the bloodstream.

How is O2 and CO2 carried in the blood?

Non-cellular innate defenses

Skin: Physical barrier. Secretes antimicrobial enzymes like defensins

Mucus: On mucous membranes. Traps pathogens. In respiratory system mucous is propelled upward by cilia via mucociliary escalator

Lysozymes: In tears and saliva. Antimicrobial compound

Complement System: Can punch holes in the cell walls of bacteria making them osmotically unstable, leading to lysis. Also triggers opsonization.

Interferons: Given off by virally infected cells. Interfere with viral replication and dispersion

Cellular innate defenses

Components of humoral immunity (adaptive immune system)

Components of cell-mediated immunity

Autoimmune vs allergic reactions

Autoimmune Conditions: A self-antigen is recognized as foreign, and the immune system attacks normal cells

Allergic Reactions: Nonthreatening exposures incite an inflammatory response

Intracellular Digestion

The oxidation of glucose and fatty acids to make energy.

Extracellular Digestion

Process by which nutrients are obtained from food. Occurs in alimentary canal.

Mechanical Digestion

Physical breakdown of large food molecules into smaller particles.

Chemical Digestion

The enzymatic cleavage of chemical bonds such as the peptide bonds of proteins or the glycosidic bonds of starches.