bsc2085 exam one⋆｡°✩

organelles

internal structures of a cell that carry out specialized metabolic tasks

example of primary active transport

sodium potassium pump

movement of molecules in sodium potassium pump:

3 Sodium ions move out of the cell, 2 potassium ions move into the cell. a form of anti-port that uses energy

what ion level is low during secondary active transport due to the Na/K pump?

sodium, because it was moved out of the cell during primary active transport

non-membranous organelles

cytoskeleton, microvilli, centrioles, cilia, ribosomes, proteasomes (do not have a surrounding membrane)

main difference between primary and secondary transport

primary uses ATP and secondary does not.

LDL cholesterol

bad cholesterol

exocytosis examples

hormone secretion, neurotransmitter release, mucus secretion, ejection of wastes, release of insulin from endocrine glands, milk sugar released by mammary glands

main difference between microvilli and cilia

microvilli is composed of microfilaments, whereas cilia is composed of microtubules, therefore making it longer

what is the main difference between a peroxisome and lysosome

a peroxisome uses molecular oxygen to digest substances, versus enzymes used in lysosomes for digestion

tay-sachs disease

A human genetic disease caused by a recessive allele that leads to the accumulation of certain lipids in the brain. Seizures, blindness, and degeneration of motor and mental performance usually become manifest a few months after birth.

start codon

AUG

cytosol

clear gel within the cell. Contains enzymes and other proteins, amino acids, ATP, etc.

The fluid WITHIN the cytoplasm

cytoskeleton

network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement

cytoskeleton functions

- Anchoring organelles

- Moving RNA and vesicles

- Permitting shape changes and movement

- structural support, determines cell shape

cytoskeleton components

microtubules, microfilaments, intermediate filaments

microfilaments

smallest, made of actin protein, form terminal web.

provide mechanical strength by anchoring cytoskeleton to plasma membrane proteins.

interact with cytosotic proteins to adjust liquidity of cytosol

intermediate filaments

within skin cells, made of protein keratin. Give cell shape and resist stress.

provide mechanical strength/durability to cell (these cells are the most stable and durable)

maintains cell shape

stabalizes organelle

microtubules

Contain protofilaments made of protein tubulin. Maintain cell shape, hold organelles, act as railroad tracks for WMP, form mitotic spindle

attaches to the centrosome

changes to this can change the cell shape

can be used as a highway system, motor proteins (kinesin and dynein) used ATP energy to move organelles

microvilli

extensions of the plasma membrane. core composed of microfilaments

provide 15-40 times more surface area to cells that have them

best developed in cells for absorption, where they are very dense and appear as a fringe called the brush border.

example of location of microvilli in cells

epithelial cells lining the small intestine for nutrient absorption

brush border

Surface of a cell covered with microvilli. increases surface area of a cell for absorption

cilia

small-hair like processes composed of microtubules

difference between cilia and microvilli

Cilia are mobile and waft so require energy, are composed of microtubules; microvilli increase SA for absorption and don't require energy and are made of microfilaments

motile cilia

respiratory tract, uterine tubes, ventricles of brain, ducts of testes. less widespread, sweep material across surface in one direction

centrioles

assembly of microtubules arranged in 9 groups of 3 each

plays important role in forming spindle apparatus

two centrioles lie perpendicular to each other within the centrosome

centrosome

A structure present in the cytoplasm of animal cells that functions as a microtubule-organizing center and is important during cell division. A centrosome has two centrioles. Clear area next to nucleus

organelles with membranes

Nucleus, mitochondria, lysosomes, peroxisomes, endoplasmic reticulum, and Golgi complex

ribosomes

small granules of protein and RNA responsible for producing proteins

read the coded genetic messages in mRNA

site of protein synthesis

found on rough ER, nucleoli, cytosol

free ribosomes

suspended in the cytosol

fixed ribosomes

attached to the endoplasmic reticulum

Rough Endoplasmic Reticulum

An endomembrane system covered with ribosomes where many proteins for transport are assembled. proteins produced here are typically destined to become plasma membrane proteins

proteasomes

dispose of surplus proteins. contains protease enzyme that break down tagged/targeted proteins into short peptides and amino acids

protease enzymes

Enzymes in the small intestine that break long peptide chains into shorter peptide chains.

what do proteasomes destroy

tagged damaged cell proteins or viral proteins

membrane flow

continuous exchange of membranes from one organelle to another via vesicles. dynamic: allows for adaption and change.

very active in secreting cells

what is the criteria for all membranous organelles (except peroxisomes/mitochondria)

either interconnected to each other or are in communication with each other through vesicles

endoplasmic reticulum

network of interconnected membranous channels called cisterns

rough ER

parallel, flattened sacs covered with ribosomes attached to the outside. produces phospholipids and proteins of nearly all cell membranes.

smooth ER

no ribosomes attached. tubular. synthesizes lipids and steroids. detoxifies alcohol and other drugs. calcium storage.

golgi complex

a system of membranous cisterns that synthesizes carbs and modifies newly synthesized proteins

transport vesicle

A tiny membranous sac in a cell's cytoplasm carrying molecules produced by the ER

golgi vesicles

become secretory vesicles and carry cell products to apical surface for exocytosis, or become lysosomes

secretory vesicles

secrete substances outside the cell by exocytosis

golgi complex polarity

cis face is closer to ER, trans face is farther away from the ER

function of golgi complex

sorts proteins, splices some, adds carbs, and packages them into membrane bound golgi vesicles.

lysosomes

package of enzymes bound by a membrane

function of lysosomes

Intracellular hydrolytic digestion of proteins, nucleic acids, complex carbs, + other substances..

primary lysosome

formed by golgi apparatus and inactive enzymes

secondary lysosome

formed when primary lysosomes fuse with damaged organelles and enzymes are activated

autophagy

digestion of cell's surplus organelles

autolysis

self-destruction of cells; decomposition of all tissues by enzymes of their own formation without microbial assistance (cell suicide)

Lyosomal storage disorders

inborn errors of metabolism characterized by the accumulation of substrates in excess in various organs' cells due to the defective functioning of lysosomes. They cause dysfunction of those organs where they accumulate and contribute to great morbidity and mortality.

peroxisomes

resemble lysosomes but contain different enzymes and are produced by endoplasmic reticulum. present in all cells, but abundant in kidney + liver

function of peroxisomes

use molecular oxygen to oxidize organic molecules. neutralize free radicals; detoxify alcohol/drugs, break down fatty acids in acetyl groups and its reactions produce hydrogen peroxide

how much of the cells energy does mitochondria produce

when active, 95%, and the other 5% comes from ATP produced outside of the mitochondria in the cytosol by Glycolysis

membranous mitochondria

organelles specialized for synthesizing ATP when oxygen is present.

known as the Powerhouse of the cell.

produces most of the cell’s energy

mitochondrial disorders are inherited from maternal side

cristae

folds in the inner membrane of mitochondria

cristae matrix

space between the cristae, Matrix contains ribosomes, enzymes used for ATP synthesis, and small circular DNA molecules called mitochondrial DNA (mtDNA)

example of lyosomal disease

Tay-Sachs disease: lack of lysomal enzyme causes a build up of lipids in brain cells, causing their death

actin filaments pair with ______ for muscle contraction

thick filaments of myosin

difference between gelatinous cytosol and fluid cytosol

gelatinous= dense network

fluid= widely dispersed network

free ribosome function

manufacture proteins for use inside the cell

fixed ribosome function

manufacture proteins for secretion or for plasma membrane

cisternae

flattened stacked membrane folds

transport vesicles

deliever contents to the golgi appartus for processing

pancreatic cells secreting digestive enzymes have extensive _____ ER

rough

reproductive cells have more _____ ER

smooth

catalase

An enzyme produced in all cells to decompose hydrogen peroxide, a by-product of cell respiration

mitochondrial energy production

glycolysis, citric acid cycle, electron transport chain

glycolsis

a series of chemical reactions in the cytoplasm of a cell that break down glucose. converts glucose to pyruvic acid IN THE CYTOSOL.

cytosolic proteins

synthesized by free ribosomes. They stay in the cytosol for their functions. dense makes cytosol more dense/gelatin, dispersed makes cytosol more fluid

functions of microfilaments

- Maintenance of cell shape (tension-bearing elements)

- Changes in cell shape

- Muscle contraction

- Cytoplasmic streaming

- Cell motility (as in pseudopodia)

- Cell division (cleavage furrow formation)

functions of microtubules

shape and support the cell, guide movement of organelles, separate chromosomes during cell division

motor proteins

kinesin and dynein, myosin use ATP energy to move organelles

spindle appartus

structure made of spindle fibers, centrioles, and aster fibers that is involved in moving and organizing chromosomes before the cell divides (during anaphase)

Connective tissue

The most abundant, widely distributed type of tissue characterized by specialized cells, solid extracellular protein fibers, ground substance, and extracellular components making up the matrix.

Functions of connective tissue

Include binding of organs, support, physical and immune protection, movement, storage, heat production, and transport.

Embryonic mesenchyme tissue

Gives rise to all other connective tissue.

Mucous connective tissue/Wharton's jelly

Found in many parts of the embryo and stem cells obtained from this jelly may have therapeutic applications.

Fibrous Connective Tissue

Comprised of fibroblasts, macrophages, leukocytes, plasma cells, mast cells, and adipocytes.

Connective Tissue Proper

Provides routes for blood/lymphatic vessels and nerves, strength, stability, and maintains the position of internal organs.

fibroblasts

produce fibers and ground substance

macrophages

arise from monocytes, phagocytize foreign material and activate immune system when they sense foreign matter

leukocytes

white blood cells, fight infection

plasma cells

arise from lymphocytes and synthesize antibodies

fasciae

The body's framework of connective tissue

Layers and wrappings that support or surround organs

hypodermis

superficial fasciae, provides insulation and padding under the skin

deep fascia

resists multi-directional force, wraps organs in capsules, found at the end of muscles as tendons and links bones as ligaments

subserous fascia

protects body cavity lining when the organs move

mast cells

secrete heparin to inhibit clotting and histamine to dilate blood vessels

Adipose tissue

Tissue where adipocytes are the dominant cell type, with space between fat cells occupied by areolar tissue, reticular tissue, and capillaries.

what is the space between fat cells occupied by

areolar, reticular tissue and capillaries

White Adipose Tissue

The most abundant type of fat tissue in adults, providing thermal insulation, cushioning organs, contributing to body contours, and secreting hormones.

Brown Adipose Tissue

Found mainly in fetuses, infants, and young children, functions as heat generation tissue by breaking down stored fats to generate heat.

Fluid Connective Tissue

Contains a fluid ground substance or matrix that suspends a mixture of cells, such as blood.

Blood

Main function is transportation. Contains erythrocytes, leukocytes, platelets, plasma, and extracellular fluid components like interstitial fluid and lymph.

erythrocytes

red blood cells that transport gases

platelets

cell fragments involved in blood clotting

extracellular fluid

fluid outside the cell