MDCAT Biology Syllabus

Biology syllabus — full chapter and topic list

Expand any chapter to see its topics and sub-topics. This is the whole examinable outline for Biology in MDCAT, not a summary of it.

1. 1

   Cell Structure

   3 topics

   • Cell Theory
   • Prokaryotic and Eukaryotic Cells
   • Cell Organelles
2. 2

   Biological Molecules

   4 topics

   • Carbohydrates
   • Proteins
   • Lipids
   • Nucleic Acids
3. 3

   Enzymes

   3 topics

   • Characteristics of Enzymes
   • Mechanism of Enzyme Action
   • Factors Affecting Enzyme Activity
4. 4

   The Cell Cycle

   3 topics

   • Phases of Cell Cycle
   • Regulation of Cell Cycle
   • Apoptosis
5. 5

   Human Physiology

   5 topics

   • Blood and Immune System
   • Nervous System
   • Digestive System
   • Excretory System
   • Musculoskeletal System

Biology flashcards for MDCAT

22 of 50 cards from the Biology deck — real questions with worked answers.

1. What are the three main postulates of the Cell Theory?

   (1) All living organisms are composed of one or more cells; (2) the cell is the basic structural and functional unit of life; (3) all cells arise from pre-existing cells by division.

2. Who first coined the term 'cell', and who proposed 'omnis cellula e cellula' (all cells from cells)?

   Robert Hooke coined the term 'cell' (1665); Rudolf Virchow proposed 'omnis cellula e cellula' (1855). Schleiden and Schwann formulated the original cell theory.

3. List four key features of prokaryotic cells that distinguish them from eukaryotic cells.

   No membrane-bound nucleus (nucleoid instead); no membrane-bound organelles; 70S ribosomes; a single circular DNA molecule; typically small ($1$–$10\ \mu m$) with a peptidoglycan cell wall (in bacteria).

4. Compare ribosome types in prokaryotes vs eukaryotes.

   Prokaryotes have 70S ribosomes (50S + 30S subunits). Eukaryotes have 80S ribosomes (60S + 40S subunits) in the cytoplasm, but 70S ribosomes inside mitochondria and chloroplasts.

5. Which organelle is called the 'powerhouse of the cell' and what is its main function?

   The mitochondrion. It carries out aerobic respiration (Krebs cycle and oxidative phosphorylation) to produce ATP. It has a double membrane with inner folds called cristae and its own circular DNA.

6. What is the function of the rough endoplasmic reticulum (RER) versus the smooth ER (SER)?

   RER (studded with ribosomes) synthesizes and processes proteins for secretion or membranes. SER (no ribosomes) synthesizes lipids and steroids, metabolizes carbohydrates, and detoxifies drugs; in muscle it stores $\ce{Ca^{2+}}$.

7. What are the roles of the Golgi apparatus?

   It modifies, sorts, packages, and dispatches proteins and lipids received from the ER, forming secretory vesicles and lysosomes. It also synthesizes certain polysaccharides.

8. What do lysosomes contain and what is their function?

   Lysosomes contain hydrolytic (digestive) enzymes active at acidic pH (~$5$). They digest worn-out organelles (autophagy), engulfed material (phagocytosis), and are called 'suicidal bags' for their role in autolysis.

9. What is the general molecular formula of carbohydrates, and what are the three main classes?

   General formula $(\ce{CH2O})_n$. Classes: monosaccharides (e.g., glucose, fructose), disaccharides (e.g., sucrose, maltose, lactose), and polysaccharides (e.g., starch, glycogen, cellulose).

10. Name the monosaccharide components of the disaccharides sucrose, maltose, and lactose.

    Sucrose = glucose + fructose; Maltose = glucose + glucose; Lactose = glucose + galactose.

11. What type of bond joins monosaccharides, and how is it formed and broken?

    A glycosidic bond joins them, formed by a condensation (dehydration) reaction that releases $\ce{H2O}$, and broken by hydrolysis which adds $\ce{H2O}$.

12. Distinguish the storage and structural polysaccharides in plants and animals.

    Plants store glucose as starch (amylose + amylopectin) and use cellulose for cell walls. Animals store glucose as glycogen (highly branched) in liver and muscle.

13. What are proteins made of, and what bond links their monomers?

    Proteins are polymers of amino acids linked by peptide (amide) bonds formed between the carboxyl group of one amino acid and the amino group of the next via condensation.

14. Describe the four levels of protein structure.

    Primary = linear amino acid sequence; Secondary = local folding into $\alpha$-helix or $\beta$-pleated sheet (hydrogen bonds); Tertiary = overall 3D folding of one chain; Quaternary = assembly of two or more polypeptide chains (e.g., hemoglobin).

15. What is the general structure of an amino acid?

    A central ($\alpha$) carbon bonded to an amino group ($\ce{-NH2}$), a carboxyl group ($\ce{-COOH}$), a hydrogen atom, and a variable R (side) group that determines the amino acid's identity.

16. What are lipids, and what building blocks form a triglyceride?

    Lipids are nonpolar (hydrophobic) biomolecules. A triglyceride (fat/oil) is formed from one glycerol molecule and three fatty acids joined by ester bonds via condensation.

17. Differentiate saturated and unsaturated fatty acids.

    Saturated fatty acids have no $\ce{C=C}$ double bonds (single bonds only), are straight, pack tightly, and are usually solid at room temperature. Unsaturated fatty acids have one or more $\ce{C=C}$ double bonds, causing kinks, and are usually liquid (oils).

18. What is the structure of a phospholipid and why is it important in membranes?

    A phospholipid has a hydrophilic (polar) phosphate head and two hydrophobic fatty acid tails (amphipathic). This dual nature drives formation of the phospholipid bilayer of cell membranes.

19. Name the two types of nucleic acids and their sugar components.

    DNA (deoxyribonucleic acid) contains deoxyribose; RNA (ribonucleic acid) contains ribose.

20. What are the three components of a nucleotide?

    A pentose sugar, a phosphate group, and a nitrogenous base (purine: adenine/guanine, or pyrimidine: cytosine/thymine in DNA, uracil in RNA).

21. State the complementary base-pairing rules in DNA and the number of hydrogen bonds in each pair.

    Adenine pairs with Thymine (2 hydrogen bonds); Guanine pairs with Cytosine (3 hydrogen bonds). In RNA, adenine pairs with uracil.

22. According to Chargaff's rule, what quantitative relationships hold between DNA bases?

    $\%A = \%T$ and $\%G = \%C$; therefore $A + G = T + C$ (total purines equal total pyrimidines).

See more Biology flashcards →

Planning Biology for MDCAT

Biology (MDCAT) FAQ