Cellular Anatomy and Physiology Flashcards

Vocabulary flashcards covering cellular anatomy, membrane transport mechanisms, cell junctions, signal transduction, and organelle functions based on lecture notes.

Cell

The smallest unit that can live on its own and makes up all living organisms and tissues of the body.

3 main parts of a cell

• cell membrane

• cytoplasm w/ organelles

• Nucleus

All cells turn into 1 of 4 types of tissue…

• Epithelial

• Connective

• Muscle (cardiac, skeletal, & smooth)

• Nerve (glucose is the only supplier)

What are the 2 types of tissues that are constantly replenishing?

Epithelial and connective

P-53 triggers…

cell apoptosis

What is cell apoptosis?

the process of a cell killing itself if it is not functional

Chemical components of a cell?

• Carbon

• Hydrogen

• Nitrogen

• Phosphorus

An organic compound is any chemical compound that contains…

Carbon

4 Major functions of the Plasma Membrane

1. Compartmentalization

2. Regulate transport

3. Signal detection / communication

4. Cell-to-cell interactions

Compartmentalization (plasma membrane)

• Determines the boundaries of the cell 

• Protect the integrity of the cell by separating the internal and external environment

Regulate transport (plasma membrane)

• Passive & active transport mechanisms 

• Receptor-mediated endocytosis 

Signal detection / communication (Plasma membrane)

• Direct contact & commo w adjacent cells thru junctions 

Components of a Lipid Bilayer

1. Phospholipids (75%)

2. Sterols (cholesterol) (20%)

3. Glycolipids (5%)

6 Major Proteins:

1. Receptors

2. Enzymes

3. Ion Channels

4. Carriers / Transport

5. Anchor / Adhesion

6. Cell Identity / “Self”

5 types of cell junctions

1. Tight Junctions (occluding junctions)

2. Adherens Junctions (zonula adherens)

3. Desmosomes (macula adherens)

4. Hemidesmosomes

5. Gap Junctions

Titin

The largest protein in the body, found in muscle tissue and composed of $27{,}000$ amino acids.

Organic Compound

Any chemical compound that contains carbon.

Compartmentalization

A major plasma membrane function that determines cell boundaries and protects cell integrity by separating the internal and external environments.

Signal Transduction

The process of transmitting molecular signals from a cell's exterior to its interior to convert chemical messages into appropriate cellular responses.

Contact Inhibition

An anticancer mechanism where normal cells arrest growth and stop proliferating upon encountering each other after forming a monolayer in a culture dish.

Amphipathic

Possessing both a polar, hydrophilic head and a nonpolar, hydrophobic tail, ensuring water cannot pass freely through the lipid bilayer.

MHC-I (“American Flag”)

proteins that are specific to a specific person

Tight Junctions

Seals cells together and prevents substances from leaking between cells

transmembrane PROs (Ex. Occludin PRO)

• Found in epithelial tissue (specifically in the lining of the digestive tract)

Adherens Junctions

Sticks neighboring cells together with a belt’ like attachment

(Ex. Cadherin PROs)

• Found in Epithelial tissue

Cadherins

A type of cell adhesion molecule (CAM) that requires calcium ions to function.

Desmosomes

very tight “spot welds”; junction formed by desmosomal PROs (Ex. Desmogleins, desmocollins); anchored to the cell’s keratin (intermediate filament); stabilize cells that stretch & contact

• Strongly holds cells together so they don’t pull apart

• Found in skin and cardiac muscle

Hemidesmosomes

Junctions that tightly connect the basal surface of cells to the basement membrane and extracellular matrix using integrins attached to laminin and collagen.

• Ingrains attach to laminin PRO & collagen in the BM

• Anchors a cell to the basement membrane underneath it

Gap Junctions

Junctions that provide direct exchange of ions, small molecules, and metabolites between the cytoplasm of two cells via fluid-filled tunnels called connexons.

• allows for fast communication

Connexons

Fluid-filled tunnels in gap junctions formed by $6$ proteins called connexins, with each cell contributing half of the tunnel.

Passive Transport

Movement of substances down a concentration gradient that does not directly require energy such as ATP.

Active Transport

Movement of molecules against a concentration gradient requiring energy (such as ATP or an electrochemical gradient) and a transport protein.

Simple Diffusion (PASSIVE)

movement of substances directly down a concentration gradient from high to low concentration.

• Ex. Oxygen, CO2, steroid hormones

Osmosis (PASSIVE)

Passive movement of water across a selectively permeable membrane.

• Ex. RBCs, kidney water regulation, plant cell turgor

Osmotic Pressure

salts inside cells cause water to be drawn in through osmosis

Oncotic Pressure

The pulling pressure on water by proteins

Hydrostatic Pressure

increases filtration by pushing fluid and solute out

Facilitated Diffusion (PASSIVE)

transport with a helping hand (moves down a gradient)

• Ex. Glucose transport

Active Transport defined.

requires energy and transport protein to move AGAINST a gradient

Direct (Primary) transport

the “uphill” pumping of a molecule or molecule across a membrane by coupling it to the hydrolysis of ATP

4 classes of ATPase Pumps

• P-Type

• V-Type

• F-Type

• ABC-type

P-Type ATPase

classic of eukaryote Plasma membrane

V-Type ATPase

Common pump on organelles

F-Type ATPase

Common pump on bacteria, chloroplasts, and mitchondrial

ABC-Type ATPase

Common to eukaryote Plasma membrane

• Help move large molecules like drugs, sugars, amino acids etc.

Indirect (secondary) Active Transport

uses 1 molecule (moving with its gradient which is HIGH to LOW) to move another molecule against that gradient (which is LOW to HIGH)

Antiport (or counterport)

2+ molecules are transported in opposite directions (Ex. Exchange of Na+ in the GI tract)

(used in secondary transport)

Symport

2+ molecules are transported in the same direction (Ex. Na+ -Glucose & Na+ -AA transport into enterocytes in the GI tract)

Vesicle Movement / Bulk

Bulk movement of substance into (endocytosis) or out of (exocytosis) the cell

Endocytosis

Brings material in

Phagocytosis

“To eat”

Pinocytosis

“To drink”

Exocytosis

vesicle fuses with the membrane & dumps contents out

Signal Transduction

process of converting information from one form to another

Rough ER

Endoplasmic reticulum studded with embedded ribosomes where protein synthesis occurs.

Smooth ER

• Further extension of Rough ER

• Not found in every cell but is found plentiful in muscles cells

• Responsible for lipid synthesis and calcium storage

Ribosomes

• Direct site of protein translation

• Have two subunits that join together

• By definition they ARE NOT organelles because they do not contain a membrane around them

Golgi Apparatus

The post office of the cell that modifies, packages, and secretes cellular products.

Lysosomes

Organelles with two phospholipid layers containing hydrolytic enzymes used to recycle or break down biomolecules.

Peroxisome

An organelle containing over $50+$ oxidative enzymes, including catalase, used to break down fatty acids and detoxify harmful substances.

Phagosomes / Autophagosomes

Vesicles that “self-eat” cellular debris and fuse with lysosomes to remove and recycle waste products.

Cristae

The inner membrane folds of mitochondria where protons associated with the electron transport chain (ETC) are found.

Cytoskeleton

A cellular framework composed of microfilaments, intermediate filaments, and microtubules that provides structural support, maintains cell shape, and enables movement.

(has to be produced)

Centriole

Structures formed exclusively during cell division to move chromosomes.

What organelle do RBCs not have?

a nucleus

Nucleus

The control center of the cell and site of DNA replication and RNA processing, absent in mature red blood cells.

Nucleolus

The ribosome factory inside the nucleus responsible for rRNA synthesis and ribosome subunit assembly.

Chromosomes

Structures containing DNA, associated proteins, and RNA that form genes.

Chromatids

One of the two identical sides of a replicated chromosome.

Centromere

The constricted region holding sister chromatids together that serves as the attachment site for spindle fibers during cell division.

Jobs of Plasma Membrane

• passive and active transport

• communication and signal sending

4 basic biomolecules

• Proteins

• Lipids

• Nucleic Acids

• Carbohydrates

Levels of Organization of structure within body

1. Chemical

2. Molecule

3. Organelle

4. Cell

5. Tissue

6. Organ

7. System

8. Organization

Factors that affect diffusion

• Lipophilic or Lipophobic

• Size/mass (smaller = faster)

• Charge (uncharged = faster)

• Concentration gradient (larger = faster)

• Temperature (hotter = faster)

• Surface Area (larger SA = faster)

• Distance / Width (shorter = faster)

RBCs & osmosis in different solutions

Hypotonic → cell swells

Isotonic → no net movement

Hypertonic → cell shrinks

4 types of signal messengers

1. Neurotransmitters

2. Endocrines / Hormones

3. Paracrine / Local Mediators

4. Autocrine / Local Mediators

Neurotransmitters

• very fast way to communicate

• released in synapse

Endocrine / Hormones

• travel in central circulation (plasma) and affect specific target cells

• Slow way to communicate but have longer half-life

Paracrine / Local Mediators

• chemicals released into ECF / ISF (not blood stream)

• affects only nearby cells

Autocrine / Local Mediators

• chemical signal affects only the cell that produced it

Autophagy defined

the catabolic process involving the degradation of a cells internal components through lysosomal machinery

• helps maintain balance between synthesis, degradation and recycling of cell products

3 Phagosome sensors

1. mTOR → senses nutrients

2. AMPK →senses energy

3. HIF →senses low oxygen

4 Nucleo Bases and which pair together?

Adenine (A)

Thymine (T)

Cytosine (C)

Guanine (G)

A pairs to T

G pairs to C

Job of Microfilaments

support cell shape and movement!

Job of intermediate filaments

provides strength, resist stretching, and maintain cell integrity

Job of Microtubules (Hollow)

serve as tracks for organelle transport

Hemolysis

the destruction of RBCs

Erythropoiesis

the process of creating RBCs through red bone morrow

What are glycoproteins?

Proteins that have carbohydrate chains attached to them

• used with communication and recognition

• immune defense

Central Dogma

concept that genetic information flows in one direction within a biological system; DNA —> RNA —> Ribosomes

Chromosomes

contain DNA and associated proteins & RNA that form genes

Chromatids

one of the two identical sides of a replicated chromosome

Centromere

constricted region that holds two sister chromatids together and serves as the attachment side for spindle fibers during cell division

Genes

The information carried by DNA is held in the sequence of pieces of DNA

Messenger RNA (mRNA)

Carries genetic information from DNA (in nucleus) to ribosome for protein synthesis

• Longest

Ribosomal RNA (rRNA)

Forms the structural and functional core of ribosomes and catalyzes peptide bond formation

• Largest

Transfer RNA (tRNA)

Carries specific amino acids to the ribosome and matches its anticodon with mRNA codon

• Smallest

Telomere

The end of a chromatid (think plastic cap of shoelace)

• If DAMAGED, then cell can no longer divide

Protein Synthesis requires 2 steps

1. Transcription

2. Translation

What is Transcription?

The 1st step of gene expression; a specific segment of DNA is copied into RNA (mRNA) by the enzyme RNA polymerase; the mRNA leaves the nucleus & heads for a ribosome