Cellular Biology Flashcards
oxidative phosphorylation
occurs in the mitochondria and is the mechanism by which the energy produced from carbohydrates, fats and proteins is transferred to ATP.
- sometimes NAD is needed to transfer ions when breaking down glucose (catabolism)
Describe the structure and function of the nucleus.
Nucleus structure - surrounded by nuclear envelope which is two layers. Nucleus contains the nucleoulous composed of ribonucleic acid, cellular DNA, and DNA-binding proteins.
Nucleus Function: Cell division and control of genetic information. Other functions also include replication and repair of DNA.
State the functions of a typical Eukokaryotic cell
Movement - muscle cells, organ cells that move items through hollow cavities
• Conductivity - chief function of nerve cells. a respond to a stimulus and is a wave of
excitement
• Metabolic absorption - all cells can take in and absorb nutrients and other substances
from their surroundings
• Secretion - mucous gland cells can synthesize new substances from substances they
absorb and then secrete the new substances as needed elsewhere
• Excretion - all cells rid themselves of waste products resulting from the metabolic
breakdown of nutrients
• Respiration - cells absorb oxygen, which transforms nutrients into energy (ATP) (happens
in mitochondria)
• Reproduction - tissue growth occurs as cells enlarge and reproduce themselves
• Communication - is vital to all cells to survive as a society of cells
Describe the structure and function of the plasma membrane.
Function - control the composition of the space, or compartment, that they enclose. Can
include or exclude various molecules and exert a powerful influence on metabolic pathways.
cell-to-cell recognition. Cellular mobility and maintenance of cellular shape.
Structure - outer surface has caveolae (storage sites for receptors and provide route for
transport into the cell). Made of lipids and proteins.
* hydrophobic heads, hydrophilic tails
- carbohydrates on cell membrane aid in intracellular recognition
passive vs. active transport
Passive transport: water and small, electrically uncharged molecules move easily through pores in the plasma membrane’s lipid layer. Occurs natrually through a semi-permeable barrier. Driven by osmosis, hydrostatic pressure, and diffusion - all depend on laws of physics and do not require life. No energy expenditure.
- Diffusion: movement from area of greater concentration to area of lesser solute concentration
* difference - in concentration of solute is concertration gradient. higher concentration on one side = larger diffusion rate
* filtration - movement of water and solutes through a membrane because of a greater pushing pressure (force) on one side of the membrane than the other side.
- hydrostatic pressure - mechanical force of water pushing against cellular membranes
* osmosis - movement of water “down” a concentration gradient. membrane must be more permeable to water than to solutes and concentration of solutes on one side must be greater than that on the other side.- osmolality: weight
- osmolarity: volume
Active transport: too large to pass through membrane objects or ligands (bound to receptors on the cell’s plasma membrane). Requires life, biologic activity, and cell’s expenditure of metabolic energy. occurs accross ONLY living membranes that 1) use energy generated by cellular metabolism 2) have receptors that can recognize and bind with the substance to be transported. exps = endocytosis, exocytosis, protein channels, receptor-mediated endocytosis.
* active mediated transport: moves molecules against or UP the concentration gradient. requires the expenditure of energy.
endocytosis vs. exocytosis
endocytosis: large molecules and fluids are transported, taken into the cell
- enfolds substances from outside the cell, invaginates, and separates from the plasma membrane.
* pinocytosis - cell drinking. ingestion of fluids and solute molecules through formation of small vesicles
* phagocytosis - cell eating. ingenstion of large particles (like bacteria) through the formaiton of large vesicles.
Exocytosis: large molecules and fluirs are expelled, taken out of the cell. Secretion of macromolecules almost alays occur in exocytosis.
2 fxns 1) replacement of portions of the plasma membrane that have been removed by endocytosis 2) release of molecules synthesized by the cells into extracellular space
What are proteins in relation to the plasma membrane?
Made of amino acids (20) and are very versatile. Integral membrane proteins only removed from membrane by detergents that solubilize the lipid. Peripheral membrane proteins are not imbedded in the bilayer but reside at one surface or the other.
Mitosis and cytokinesis
reproduction of body cells (minus sperm and egg). must double in mass and duplicate it’s contents.
mitosis = nuclear divison
cytokinesis = cytoplasmic division
Phases:
S phase (synthasis) – G2 phase gap (protein and RNA synthesis occurs — M phase mitosis (nuclear and cytoplasmic division) — G1 phase
1. Interphase: G1, S, G2 phases
- longest phase of the cell cycle. chormatin starts as long and by end of it is coiled (short and thick)
2. M phase:
- prophase: the appearance of chromosomes, to chromatids (2 identical halves)
- metaphase: chormosomes pulled to opposite sides of the cell then organize in the middle of the cell. nuclearn envelope goes away
- anaphase: centromeres split and chromatids are pulled apart. by the end, 46 chromosomes lie at each side of the cell.
- telophase: nuclear membrane is formed around each group of 46 chromosomes and the chromosomes begin to uncoil. cytoplasm divides into two equal parts. two daughter cells are formed in the end of telophase.
the stimulation of cell proliferation by growth factors
Growth Factors = cytokines = peptides that transmit signals within and between cells. Major role in regulation of tissue growth and development.
- platelet derivded growth factor (PDGF) - stimulates proliferation of connective tissue cells and neurologic cells
- Epidermal Growth Factor (EGF): epidermal cells and other types
- insulin-like growth factor 1 (IGF-1): collaborates with PDGF and EGF stimulates fat cells and connective tissue cells
- Vascular endothelial growth factor (VEGF): mediates functions of cells
- insulin like growth factor 2 (IGF-2): stimulates or inhibits response of most cells to other growth factors
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Pattern Formation
the process by which differentiated cells create tissues and organs.
- to form tissues cells must: exhibit intercellular recognition and communication, adhesion, and memory.
- Specialized cells can sense their environment through signals, such as growth factors, from other cells. This ensures that new cells are only produced when and where they are needed.
- other cells have adhesion molecules in their plasma membranes that stick to selective other cells
epithelial tissue
1) simple squamous epithelium
- single layer of cells
- Location: line blood vessels, pulmonary alveoli (air sacs)
- Function: diffusion and filtration, separation of blood from fluids in tissue, separation of air from fluids in tissue
2) Stratified squamous epithelium
- two or more layers, with cuboidal cells closest to basement membrane
- location: epidermis of skin, linings of mouth, pharynx, esophogus, anus
- Fucntion: protection and secretion
3) transitional epithelium
- vary in shape from cuboidal to swuamous. When bladder is full the cuboidal cels stretch and all are flat
- location: lining of urinary bladder and other hollow structures
- function: stretching that permits expansion of hollow organs
4) simple cuboidal epithelium
- simple cuboidal cells, rarely stratified (layered)
- location: glands (thyroid, sweat, salivary), parts of kidney tubule and outer covering overy
- function: secretion
5) simple columnar epithelium (and ciliated - in bronchi of lungs, nasal cavity oviducts)
- large amounts of cytoplasm and cellular organelles
- location: lining of digestive tract
- function: secretion and absorption from stomach to anus
6) stratified columnar epithelium
- small and rounded basement membrane
- location: linings of epiglottis, part of pharynx, anus and male urethra
- function: protection
Pseudostratified ciliated columnar epithelium
- all cells in contact with basement membrane
- location: linings of large ducts of some glands, male urethra, respiratory passages, eustachian tubes of ears
Connective Tissue
1) loose or areolar tissue
- unorganized, spaces between fibers
- location and function : attaches skin to underlying tissue, holds organs in place by filling spaces, supports blood vessels
2) dense irregular tissue
- dense, compact, areolar tissue, with fwer cells and greater number of closely woven collagenous fibers than in loose tissue
- location and function: demris layer of the skin; acts as protective barrier
3) dense, regular (white fibrous) tissue
- collagenous fibers and some elastic fibers, tightly packed into parallel bundles, with only fibroblast cells
- location and function: forms strong tendons and muscles, ligaments and joints, some fibrous membranes and fascia that surround organs and muscles
4) elastic tissue
- elastic fibers, some collagenous fibers, fibroblasts
- location and function: lends strength and elasticity to walls or arteries, trachea, vocal chords, and other structures.
5) adipose tissue
- fat cells dispersed in loose tissues; each cell contains a large droplet of fat
- location and function: stores fat, which provides padding and protection
6) cartilage (hyaline, elastic, fibrous)
- collagenous fibers embedded in a firm matrix; no blood supply
- location and function: gives form, support, flexibility to joints, trachea, nose, ear, vertebral disks, embryonic skeleton, and many internal structures
7) Bone
- rigid connective tissue consisting of cells, fibers, ground substances, minerals
- location and function: lends skeleton rigidity and strength
8) special connective tissues
* plasma - fluid, serves as matrix for blood cells
muscle tissues
1) Skeletal Muscle
long, cylindrical cells that extend throughout he length of the muscles
- striated myofibrils, many nuclei on periphery
- attached to bones directly or through tendons
2) cardiac muscle
- branhing networks throughout muscle tissue, striated myofibrils
- cells attached end-to-end at intercalated disks; tissue forms walls of heart (myocardium)
- involuntary pumping action of the heart
3) smooth (visceral) muscle
- long spindles that taper to a point, absent of striated myofibrils
- walls of hollow internal structures, such as digestive tract
- voluntary and involuntary contractions that move substances through hollow structures.
Describe cellular catabolism and the transfer of energy needed to accomplish other cellular processes
Energy releasing process of cellular metabolism (task of maintaining essential cellular functions)
- phase 1: DIESTION extracellular digestion of large molecules to simple subunits (food — proteins, lipids, fats —- amino acids, simple sugars, fatty acids)
- Phase 2: GLYCOLYSIS/OXIDATIONintracellular breakdown of subunits to acetyl CoA accompanied by production of limited ATP and NADH (glycolosis creates ATP and turns into pyruvate or acetyl CoA)
- Phase 3: CITRIC ACID CYCLE production of NADH yielding ATP via electron transport; waste products are extorted (citric acid cycle, excretion)
- ATP - transfers energy when glucose breaks down in presence of o2 or co2. 7 kal per ATP
anaerobic glycolysis
when o2 is not available to the electron transport chain, ATP will not be formed by mitochondria.
- conversion of glucose to pyruvic acid with simultaious production of ATP.
- One molecule of glucose = 2 ATP and 2 pyruvate – then they enter the citric acid cycle
- if not O2, pyruvate is converted to lactic acid . once o2 is restored, then lactic acid turns abck into pyruvic acid or glucose.
- not as effective as aerobic cycle
passive vs. active transport
Passive transport: water and small, electrically uncharged molecules move easily through pores in the plasma membrane’s lipid layer. Occurs natrually through a semi-permeable barrier. Driven by osmosis, hydrostatic pressure, and diffusion - all depend on laws of physics and do not require life. No energy expenditure.
- Diffusion: movement from area of greater concentration to area of lesser solute concentration
* difference - in concentration of solute is concertration gradient. higher concentration on one side = larger diffusion rate
* filtration - movement of water and solutes through a membrane because of a greater pushing pressure (force) on one side of the membrane than the other side.
- hydrostatic pressure - mechanical force of water pushing against cellular membranes
* osmosis - movement of water “down” a concentration gradient. membrane must be more permeable to water than to solutes and concentration of solutes on one side must be greater than that on the other side.
Active transport: too large to pass through membrane objects or ligands (bound to receptors on the cell’s plasma membrane). Requires life, biologic activity, and cell’s expenditure of metabolic energy. occurs accross ONLY living membranes that 1) use energy generated by cellular metabolism 2) have receptors that can recognize and bind with the substance to be transported. exps = endocytosis, exocytosis, protein channels, receptor-mediated endocytosis.
endocytosis vs. exocytosis
endocytosis: lage molecules and fluids are transported, taken into the cell
Exocytosis: large molecules and fluirs are expelled, taken out of the cell.
action potential’s effect on the plasma membrane
*resting membrane potential - all cells are electrically polarized and inside of cell is more negative than outside. This is the difference in electrical charge more potassium inside cells and calcium outside cells
* ACTION POTENTIAL - when a nerve or muscle cell receives a simulus taht excedes the membrane threshhold value, a rapid change occurs in the resting membrane potential.
.. as a result, the cell membranes become more permeable to sodium so sodium moves into the cell then the moves from a negative value to 0. (depolarization)
…repolarization is the negative polarity of the resting membrane potential is reestablished. potassium starts to comes in and evens out sodium.
- hyperpolarized = membrane potential is more negative than normal (less excitable state). strong stimulus is needed to generate an action potential
- hypopolarized = membrane potential is more positive than normal, weaker than normal stiumlus is needed to reach threshhold potential.
Mitosis and cytokinesis
reproduction of body cells (minus sperm and egg)
mitosis = nuclear divison
cytokinesis = cytoplasmic division
the stimulation of cell proliferation by growth factors
Growth Factors = cytokines = peptides that transmit signals within and between cells. Major role in regulation of tissue growth and development.
- platelet derivded growth factor (PDGF) - stimulates proliferation of connective tissue cells and neurologic cells
- Epidermal Growth Factor (EGF): epidermal cells and other types
- insulin-like growth factor 1 (IGF-1): collaborates with PDGF and EGF stimulates fat cells and connective tissue cells
- Vascular endothelial growth factor (VEGF): mediates functions of cells
- insulin like growth factor 2 (IGF-2): stimulates or inhibits response of most cells to other growth factors
Pattern Formation
the process by which differentiated cells create tissues and organs.
epithelial tissue
1) simple squamous epithelium
- single layer of cells
- Location: line blood vessels, pulmonary alveoli (air sacs)
- Function: diffusion and filtration, separation of blood from fluids in tissue, separation of air from fluids in tissue
2) Stratified squamous epithelium
- two or more layers, with cuboidal cells closest to basement membrane
- location: epidermis of skin, linings of mouth, pharynx, esophogus, anus
- Fucntion: protection and secretion
3) transitional epithelium
- vary in shape from cuboidal to swuamous. When bladder is full the cuboidal cels stretch and all are flat
- location: lining of urinary bladder and other hollow structures
- function: stretching that permits expansion of hollow organs
4) simple cuboidal epithelium
- simple cuboidal cells, rarely stratified (layered)
- location: glands (thyroid, sweat, salivary), parts of kidney tubule and outer covering overy
- function: secretion
5) simple columnar epithelium (and ciliated - in bronchi of lungs, nasal cavity oviducts)
- large amounts of cytoplasm and cellular organelles
- location: lining of digestive tract
- function: secretion and absorption from stomach to anus
6) stratified columnar epithelium
- small and rounded basement membrane
- location: linings of epiglottis, part of pharynx
Connective Tissue
- blood, bone, fat, lymph
1) loose or areolar tissue
- unorganized, spaces between fibers
- location and function : attaches skin to underlying tissue, holds organs in place by filling spaces, supports blood vessels
2) dense irregular tissue
- dense, compact, areolar tissue, with fwer cells and greater number of closely woven collagenous fibers than in loose tissue
- location and function: demris layer of the skin; acts as protective barrier
3) dense, regular (white fibrous) tissue
- collagenous fibers and some
4) elastic tissue: collagen. walls of arteries, trachea, coeval chorus
5) adipose tissue: stores fat
6) cartilate (hyaline, elastic, fibrous): no blood supply, firm matrix of cells
7) bone: rigis connective tissue with cells, fibers, ground substances, minerals
8) special = plasma
skeletal/muscular muscle
long, cylindrical cells that extend throughout he length of the muscles
- striated myofibrils, many nuclei on periphery
- attached to bones directly or through tendons
nervous tissue
composed of highly specialized cells called neurons, which receive and transmit electrical impulses rapidly accross junctions called synapses.
- neurons and glial cells
Golgi complex
- responsible for processing and packaging proteins onto secretory vesicles
- endocytosis: things coming into cell go through the golgi to figure out what it is, where it needs to go.
- exocytosis: packages products for secretion through the golgi
- packager, shipper and receiver (packaging department)
- exocytosis and endocytosis
- packages proteins for export and forms secretory vessels
The Golgi apparatus receives proteins and lipids (fats) from the rough endoplasmic reticulum. It modifies some of them and sorts, concentrates and packs them into sealed droplets called vesicles. Depending on the contents these are despatched to one of three destinations:
Destination 1: within the cell, to organelles called lysosomes.
Destination 2: the plasma membrane of the cell
Destination 3: outside of the cell.
