Patho Unit 1 - Cellular Structure & Function

define microcephaly and how it occurs

condition where a baby's head is much
smaller than expected due to mutations in centrosomal proteins

define dwarfism and how it occurs

shorts stature due to mutations in centrosomal proteins

how are many skin diseases formed

malfunctions in keratin (protein)

how are diseases like parkinson’s and alzheimer’s formed

malfunctions of microtubules (part of cell’s cytoskeleton and involved in cellular transport)

what are the three smilar abilities cells share

exchange material, obtain energy from organic nutrients, and manufacture complex molecules

what are the features of a prokaryotic cell

lack nucleus and most cellular organelles, genetic material circular/double stranded, one chromosome, and asexual reproduction

what are the features of a eukaryotic cell

possess nucleus and organelles, genetic material linear and double stranded, more than one chromosome, sexual reproduction

three main parts of eukaryotic cells

nucleus, cytoplasm, plasma membrane

functions of plasma membrane

acts as a barrier, selective permeability, identifies the cell to other cells

how does the plasma membrane act as a barrier

separates intracellular fluid (ICF) from extracellular
fluid (ECF)

what does selective permeability do

controls what goes in and out of cell

what substances can pass freely through plasma membrane?

small, non-charged, non-polar, lipid-soluble substances pass freely (water is an exception)

what makes up the composition of the plasma membrane

lipids (bilayer), proteins, and carbohydrates

describe the phospholipids in the plasma membrane

amphipathic (hydrophilic head and hydrophobic tail) and arranged in a bilayer

describe what cholesterol does in the plasma membrane

at warm temps, it stiffens the membrane and at cold temps, it maintains its fluidity by preventing tight packing

what are the two kinds of membrane proteins?

integral and peripheral membrane proteins

describe integral membrane proteins

they penetrate the hydrophobic region of the cell membrane

what membrane protein reaches across both sides of the bilayer

transmembrane proteins

where are peripheral membrane proteins found?

bound to surface of the membrane on the inner side

which membrane protein can attach to phosphate head or to integral proteins?

peripheral membrane proteins

what is the glycocalyx?

layer of glycolipids and glycoproteins on the surface of various cell types

what are the functions of the glycocalyx?

in cell-cell recognition, communication, and adhesion

define membrane transport

the movement of materials into and out of a cell

what are the three types of membrane transport?

passive, active, and vesicular transport

which membrane transports require energy?

active and vesicular transport

define passive transport

materials moving in or out of a cell requiring no energy

define simple diffusion

small, non-polar molecules move across the membrane through a concentration gradient

what are the two kinds of facilitated diffusion?

channel-mediated and carrier-mediated

define channel-mediated diffusion

channel proteins provide corridors to cross membrane

define carrier-mediated diffusion

carrier proteins change shape to transport molecules across membrane

describe what happens in osmosis

water moves from dilute to concentrated solution

define tonicity

the capability of a solution to modify the volume of cells by altering their water content

what happens in an isotonic solution?

IFC is the same concentration as cytosol so no water moves in or out of the cell

what happens in a hypotonic solution?

IFC is less concentrated than cytosol so water enters the cell

what happens in a hypertonic solution?

IFC is more concentrated than cytosol so water leaves the cell

define active transport

substances move against their concentration gradient (low to high) and require ATP

what is active transport performed by?

specific proteins embedded in the membranes

why is active transport important?

allows cells to maintain concentration gradients that differ from their surroundings

how does a sodium-potassium pump work?

2 K+ ions move into the cell and 3 Na+ ions move out of the cell (both against their gradient with ATP)

define vesicular transport

large molecules, such as polysaccharides and proteins, cross the membrane in bulk via vesicles (requires ATP)

define exocytosis

transport vesicles fuse with the plasma membrane, releasing their contents into the extracellular fluid

what glands perform exocytosis

merocrine, apocrine, and holocrine glands

define endocytosis

materials move into a cell in a vesicle formed from the plasma membrane

define phagocytosis

cellular eating - a cell engulfs a particle into a vacuole

define pinocytosis

cellular drinking - molecules dissolved into droplets are taken up when ECF is “gulped” into tiny vesicles

define receptor-mediated endocytosis

binding of ligands to receptors to trigger vesicle formation

define cytosol

liquid containing water, nutrients, ions, dissolved gases, waste products (IFC)

what do ribosomes do?

they are the site of protein synthesis and translate mRNA into a protein

what are the two types of ribosomes?

bound and free ribosomes

what do bound ribosomes do?

attach to external ER and synthesize proteins for export

what do free ribosomes do?

suspended within cytosol and synthesize protein for internal purposes

what three protein filaments make up the cytoskeleton?

microtubules, intermediate filaments, and microfilaments

describe microtubules

the largest protein filament and is important in cell division

describe intermediate filaments

reinforce cell’s interior and keep its shape by holding the organelles in proper position

describe microfilaments

they are actin, used in contractile cells

what is epidermolysis bullosa simplex?

fragility of the skin that results in non-scarring blisters and erosions from the dysfunction of intermediate filaments in basal keratinocytes

what are the non-membrane bound organelles?

ribosomes and cytoskeleton

what are the membrane bound organelles?

mitochondria, lysosomes, rough ER, smooth ER, and golgi apparatus

what are mitochondria important for?

aerobic dependent cellular respiration and ATP

what are lysosomes for?

contain digestive enzymes

what does rough ER do?

protein production by ribosomes

what does smooth ER do?

deals with production/transport of lipids and detox of harmful compounds

what does the golgi apparatus do?

modifying, sorting, and packing proteins (amazon apparatus)

what is Tay-Sachs disease?

a hexosaminidase A deficiency (progressive destruction of nervous system)

what kind of disease is Tay-Sach’s disease?

a lysosomal storage disease (digestion of certain cellular substances does not occur)

in your body, what are the one cells without a nucleus?

red blood cells

define glycolysis

the anaerobic process by which energy is liberated from glucose (net gain of 2 ATP)

if oxygen is scarce (anaerobic conditions), this leads to what?

pyruvic acid/lactic acid

if oxygen is plentiful (aerobic conditions), most cells convert pyruvic acid to?

acetyl coenzyme A

what are the levels of structural organization in the body?

chemical, cellular, tissue, organs, systems