Dental Board Exam Reviewer

CELL MEMBRANE

• Phospholipid bilayer

  • Hydrophilic head (water-loving)

  • Amphipathic (having both hydrophilic and hydrophobic parts)

  • Hydrophobic tail

• Aka "Plasma membrane" or "Cytoplasmic membrane"

• Semi-permeable membrane that regulates the passage of substances in and out of the cell

NUCLEUS

• Covered by bilayered membrane (phospholipid bilayer) called Nuclear Envelope (porous, aka nuclear pores)

• Contains DNA and RNA; has structures made up of chromatin

• Two types of chromosomes:

  • Autosomes: do not determine the sex of an individual

    • Total of 44 autosomes

  • Sex chromosomes: X & Y

    • Total of 2 sex chromosomes

• Chromosome: thread-like structures that carry genetic information; contains a single double-stranded DNA molecule; humans have 46 chromosomes (23 pairs)

• Chromatin: material that makes up chromosomes; complex of DNA and its associated protein (DNA + Histones); "beads on string" appearance

  • Histones guide the coiling of DNA

• Chromatid: chromosome copy after DNA replication

• Sister Chromatids: chromatids that are bound to each other by a Centromere
  *Contains the Nucleolus: structure found within the nucleus responsible for Ribosomal synthesis; ribosomes are formed here and used for protein synthesis

TYPES OF CELLS

• Two types of cells in multicellular organisms:

  • Somatic cells: spermatogonium, oogonium

    • Somatic cells have 46 chromosomes (2n)

  • Sex cells: egg cells, sperm cells

    • Sex cells have 23 chromosomes (n)

KARYOTYPES

• 47, XY, +21 Karyotype = Down Syndrome (male trisomy 21); patient has taurodontism (enlarged pulp)

• Klinefelter syndrome: male 47 XXY karyotype

• Turner's syndrome: female 45, XO karyotype

SKIN LESIONS

• Erythema Multiforme

  • Bull's eye lesion/target lesion

  • Type 4 hypersensitivity (delayed type hypersensitivity)

  • Caused by drugs, plants, or insect bites

• Stevens Johnson Syndrome

  • Progression of erythema multiforme

  • Has fluid-filled lesions

  • Target lesion progresses to bullae with necrosis

• Toxic Epidermal Necrolysis

  • Maximal form of Stevens-Johnson syndrome

  • Generalized necrotizing of the entire body

• Lyme Disease

  • Skin rash aka erythema migrans (bigger size, up to 5-12cm)

  • Bacterial infection due to Borrelia burgdorferi

MITOCHONDRIA

• Powerhouse of the cell; ATP source of energy

• Contains folds known as Cristae

• Site of:

  • Kreb cycle/Citric acid cycle/Tricarboxylic acid cycle

  • Oxidative Phosphorylation (responsible for ATP production)

MECHANISMS FOR ATP PRODUCTION

• Glycolysis (Cytoplasm)

  • Breakdown of glucose yields 2 ATP, 2 Pyruvic acid, 4 Hydrogen

• Kreb Cycle (Mitochondria)

  • Yields 2 ATP, 16 Hydrogen, 4 CO_2, 2 Coenzyme A

• Oxidative Phosphorylation (Electron Transport Chain of Mitochondria)

  • Requires water to breakdown ATP

  • Yields 34 ATP

• Direct Phosphorylation (Cytoplasm)

  • Primarily used in the muscles

  • Yields 1 ATP, 1 Creatine

  • Note: Creatine in the urine indicates kidney disease

• Adenosine triphosphate -

  • ATPase - enzyme used to breakdown ATP

GLUCONEOGENESIS AND GLYCOGENOLYSIS

• Gluconeogenesis: converting glucose to non-glucose

• Glycogenolysis: breaking down of glycogen to glucose

RIBOSOMES

• A non-membrane bound organelle which is responsible for Protein Synthesis

• Composed of rRNA that are created in the Nucleolus

• Proteins are made of Amino Acids (total of 20 amino acids)

• Amino acids are made of CHON (carbon, hydrogen, oxygen, nitrogen)

TYPES OF AMINO ACIDS

• Essential - Need in our diet, most are not produced by the human body, egg is rich in amino acid

  • Threonine

  • Lysine

  • Methionine

  • Valine

  • Phenylalanine

  • Leucine

  • Tryptophan

  • Isoleucine

  • Histidine

• Non-Essential - Produced in the body, okay even without it in the diet

  • Proline

  • Glycine

  • Alanine

  • Arginine

  • Serine

  • Cysteine

  • Aspartic Acid

  • Glutamic Acid

  • Asparagine

  • Glutamine

  • Tyrosine

• Form amino acids can be absorb in the GI TRACT

• Protein - cannot be absorb in GIT, uses enzyme in order to breakdown protein, as they are macromolecules, so they can't pass through the membranes of gastrointestinal tract

NITROGENOUS BASES

• Purines

  • Adenine (DNA & RNA)

  • Guanine (DNA & RNA)

• Pyrimidines

  • Thymine (DNA)

  • Uracil (RNA)

  • Cytosine (DNA & RNA)

RNA

• All RNA comes from transcription, but they still need to be modified

• Types of RNA

  • rRNA (Ribosomal RNA): forms RIBOSOMES (translates the mRNA)

  • mRNA (Messenger RNA): carries genetic information of DNA; end product of TRANSCRIPTION

  • tRNA (Transfer RNA): carries amino acids to the ribosomes during TRANSLATION

ENDOPLASMIC RETICULUM

• ROUGH ENDOPLASMIC RETICULUM

  • Contains Ribosomes giving it a "Rough" appearance

  • Site of protein synthesis

• SMOOTH ENDOPLASMIC RETICULUM

  • Does not contain Ribosomes giving it a "Smooth" appearance

  • Site of:

    • Steroid synthesis - formation of steroidal hormones like testosterone, estrogen, progesterone, etc.

    • Lipogenesis - process of fat formation

    • Detoxification of different substances (drugs, alcohol etc.)

NON-INSULIN DEPENDENT TISSUES

• Brain

• RBC

• Intestine

• Cornea

• Kidney

• Liver

• Exercising skeletal muscle

GOLGI APPARATUS

• Packages and modifies the products made by the RER.

LYSOSOMES

• Packaged products of Golgi apparatus

• Contains hydrolytic "Lysozymes" or enzymes

• Responsible for Apoptosis or "Programmed cell death"

• Which initiates apoptosis? - MITOCHONDRIA

TYPES OF NUCLEAR CHANGES DURING APOPTOSIS

• Pyknosis: Nucleus shrinks and chromatin condenses

• Karyorrhexis: Fragmentation of the nucleus and the chromatin disintegrates

• Kayolysis: Nucleus dissolution, nuclear membrane remains intact; nucleus lang nag change

FASTING BLOOD SUGAR

• 80-120mg/dl

• Hyperglycemia - it is high and normal after you eat

• Pancreas (beta cells) - secrete INSULIN kapag mataas sugar level

INSULIN EFFECTS

• 1st effect of insulin --> increase glucose uptake by the cell and usage, decrease sugar level sa blood because insulin helps to absorb more glucose

• Glycogenesis - will increase if you still eat too much

  • conversion of glucose in to glycogen

  • stored chain of glucose

  • most cell can store glycogen but most glycogen is stored in liver and skeletal/smooth muscle (more on the liver)

  • 2 pounds is the maximum amount of glycogen we can store

• Increase Fatty acid synthesis (excess glucose --> Fatty acid), stored in adipocytes no limitations in storing Fats

ALPHA CELLS SECRETION

• pancreas (alpha cells) starts to secrete glucagon (insulin inhibition)

• Glycogenolysis: breaking down of glycogen to glucose

• Gluconeogenesis: converting non-glucose (lipids, protein) to glucose

DOESN'T NEED INSULIN FOR GLUCOSE TO ENTER

• Brain

• Rbc

• Intestine

• Cornea

• Kidney

• Liver

• Exercising skeletal muscle resting (insulin dependent) - kapag nag exercise nagiging non insulin dependent

ENZYMES

• Substrate - is a molecule in which an enzyme reacts with

• Holoenzyme (or haloenzyme): an active or complete enzyme

• Apoenzyme: inactive protein component of an enzyme; needs either co-enzyme/co-factor to be completed - helps in the process

• Co-enzyme: carrying molecule; organic molecule (carbon based); transport molecule, commonly electrons; apoenzyme complete the coenzyme

• Co-factor: helping molecule; completes an apoenzyme to function; stabilizes the enzyme - sometimes directly involved in the enzymatic reaction, ex: vit b

CENTROSOME

• Holds the chromosomes during cellular division

• Contains pair of Centrioles made of microtubules arranged in "cartwheel pattern"

CELLULAR ACCESSORIES

• Microvilli

  • Brush border appearance

  • Increases surface area of a cell that increases its Absorption property

  • Example of location: Epithelium of Stomach to 2/3 Anus (Simple Columnar with Microvilli)

  • stratified squamous is generally seen in the parts ng body na with friction or nakakaskas

  • terminal 1/3 of anus is lined with stratified squamous - tries to move something

• Cilia

  • axoneme-core of the cilia& Flagella that is made up of microtubules

  • 9+2 pattern" or "9+0 pattern" arrangement of microtubules

  • Example of location: Upper part of respiratory tract and Fallopian tube brushes the egg cell

  • Respiratory Epithelium (Upper respiratory tract) - Pseudostratified columnar ciliated with goblet cells

• Flagella

  • along with tail; para gumalaw

  • For motility of cell - Made up of axoneme

  • For motility of the cell and it is longer than cilia

• Types of Flagella

  • Atrichous - absence of flagellum

  • Monotrichous - single flagellum

  • Amphitrichous - flagella are present at both ends of the microorganism

  • Lophotrichous - tufts of flagella at one end of the microorganism

  • Amphilophotrichous - tufts of flagella at both ends of the microorganism

  • Peritrichous - flagella are found around the microorganism

• Chemotaxis? movement of microorganism due to a chemical stimulus

• What initiates flagellar activity and chemotaxis? - chemotactic agents/Factor

• Mitochondria of the sperm are located in? Located in the tail of sperm cell / midpiece

• Sperm penetrates the egg cell using?-acrosome - 1 enzyme seen here is hyaluronidase

• The tail of a sperm cell is made up of? Axoneme/ microtubules

CELLULAR DIVISION

• Interphase - it is the longest phase of cellular division

  • G1 Phase

    • "First gap phase"; cell grows and still function as usual

  • S Phase

    • "Synthesis phase"; DNA replication; RNA synthesis

  • G2 Phase

    • "Second gap phase"; Cells prepare for mitosis; Organelles double in number

• A cell that has already stopped from dividing is said to be in which stage of cellular division? - Go phase --> ex: Neurons, cardiac cells, skeletal muscle cells, mature red blood cells

MITOSIS (PMAT)

Division of Somatic cells; results in 2 genetically identical daughter cells (Diploid cells)

• Prophase

  • Nuclear membrane and nucleolus disintegrate

  • Chromatin coils and condenses (chromatid) and forms chromosomes

  • Centrioles in centrosome replicates and move towards opposite poles

• Metaphase

  • Mitotic spindles from centrosomes attach to centromere

  • Chromosomes ALIGN AT THE EQUATOR of the cell

• Anaphase

  • Chromosomes SPLIT (become chromatids) going towards opposite poles

• Telophase

  • Nuclear membrane reappears

  • Cleavage furrow forms

• Cytokinesis: cytoplasm divides into two

• Steps 1 to 4 is also known as? - Karyokinesis-division of cell nucleus during mitosis

MEIOSIS

Division of sex cells

• Germ line cells (46 chromosomes) - parent cells

• Interphase - same as mitosis

• Meiosis 1

  • Prophase 1

    • Same as mitosis

    • What is the phenomenon wherein homologous chromosomes pair during meiosis? - synapsis

    • Sharing of DNA of two homologous chromosomes, also known as the "Crossing-over" or "Chiastmata formation" of chromosomes is called? - Recombination process: nagpapalitan ng genetic material; mixture of parents cells

  • Metaphase 1: Same as mitosis

  • Anaphase 1 --> shuffle chromosome

    • Same as mitosis, but homologous chromosomes move towards opposite poles

  • Telophase 1 and Cytokinesis 1 : Same as mitosis

  • Cytokinesis 1

    • Forms 2 UNIQUE HAPLOID daughter cells for sperm (23 chr)

    • Forms 1 UNIQUE HAPLOID Secondary oocyte and 1 POLARY BODY for egg cell (23 chr)

• Meiosis 2 - UNIQUE HAPLOID daughter cells enter Meiosis 2 (23 chr)

  • Prophase 2 : Same as above mitosis -> NO SYNAPSIS and RECOMBINATION!

  • Metaphase 2: Same as mitosis

  • Anaphase 2: Same as mitosis

  • Telophase 2 and Cytokinesis 2: Same as mitosis

  • Cytokinesis 2

    • Forms 4 UNIQUE HAPLOID daughter cells for sperm (23 chr)

    • Forms 1 UNIQUE MATURE HAPLOID oocyte and 3 polar bodies for egg cell (23 chr)

BODY COMPOSITION

• Body Fluid (Water) -60% of body weight

  • 2/3 intracellular - cytoplasm

  • 1/3 extracellular

    • interstitial = 1/3

    • intravascular= 2/3

• Proteins -17%

• Fats -15%

• Carbohydrates - 1%

• Others - 7%

• Blood volume - 8% of body weight (5-7%), blood volume is proportion to blood pressure, Blood Flow = shock (loss of blood Flow)
  *psychogenic shock - when a px sees blood tas nahimatay

TYPES OF CELLULAR TRANSPORT

• Passive Transport - Movement of molecules across the cell membrane without using ATP

  • Simple Diffusion - Aka Passive Diffusion + to decrease concentration - For small molecules

    • solute molecule that are dissolved, solvent-molecule that dissolves

    • Movement of solutes from a higher concentration gradient to a lower concentration gradient.

    • E.g., movement of molecules across blood vessels, gas exchange

  • Facilitated diffusion - aka Carrier-mediated transport since it uses carrier proteins - For bigger molecules

    • E.g., glucose transport across the cell membrane

  • Osmosis - movement of solvent across a semi-permeable membrane from low osmotic pressure to high osmotic pressure (↓ to ↑)

    • increase concentration = increase osmotic pressure

    • Osmotic pressure - determined by solutes dissolved in the solution.

    • infarction most common sa heart, least common in liver

    • Hypertonic - high concentrations of solute ex: tubig dagat, Cells in hypertonic solution results to Shrinkage

    • Hypotonic - low concentration of solute, Cells in hypotonic solution results to Cell Bursting

    • Isotonic - solution has same solute concentration of the body cells, ex; tears (0.9 NaCl)

    • What is the most important protein that increases the osmotic pressure of the blood? - albumin - From liver; most numerous protein in the blood
      Saliva in the Oral Cavity is HYPERTONIC, HYPOTONIC or ISOTONIC? - hypotonic but not secreted as hypotonic initial saliva from the acinar cells are first ISOTONIC but as is passes through the salivary glands which absorb the NaCl it becomes hypotonic pag dating sa oral cavity

• Active Transport

  • Movement of molecules from low concentration gradient to high concentration gradient that uses ATP

  • Example:

    • Na-K pumps (muscle) and Proton pumps (stomach) - stomach needs a lot of hydrogen to maintain hydrochloric acid at least 1-3

  • power of hydrogen-ph (7 = increase hydrogen, pH<7=acidic, pH 7=neutral, ph>7=alkaline - decrease hydrogen
    *omeprazole (proton pump inhibitors)

• Bulk Transports:

  • Exocytosis - substance exits a cell via vesicles

  • Endocytosis - substance enters a cell placing it in a vesicle

ELECTROLYTES

• cation = +