CIS Hu Phys Ch. 3

Cells, cellular respiration, circadian rhythm, and cancer

Microvilli

Microvilli

Membrane extensions containing microfilaments; increase surface area to help with absorption

differentiation

The process of gradual specialization (of a daughter cell’s function/structure)

Totipotent cells

Cells that are able to develop into any cell in the body

Four types of tissue

Epithelial; connective; muscle; neural

extracellular fluid

watery medium that surrounds cells

interstitial fluid

watery medium between tissue cells

cytoplasm

gelatinous fluid between nuclear membrane and plasma membrane

cytosol

fluid part of cytoplasm; aka intracellular fluid

organelles

“little organs”, intracellular structures with specific functions

membranous organelles

isolated from the cytosol by phospholipid membranes. examples:

• peroxisomes

• lysosomes

• golgi apparatus

• nucleus

• endoplasmic reticulum (ER)

• mitochondria

nonmembranous organelles

not completely enclosed by membranes; usually in direct contact with cytosol. examples:

• cytoskeleton

• microvilli

• centrioles

• cilia

• ribosomes

peroxisome

vesicles containing degradative enzymes; break down acids, compounds, and neutralize toxic compounds

lysosome

vesicles containing digestive enzymes; break down large organic compounds, damaged organelles, and pathogens

golgi apparatus

stacks of cisternae containing chambers; modify and pack proteins

nucleus

nucleoplasm containing enzymes, proteins, etc; surrounded by nuclear envelope (double membrane); controls metabolism, stores/processes genetic info, controls protein synthesis

endoplasmic reticulum

network of membranous sheets and channels extending throughout cytoplasm; synthesize secretory products, store and transport substances inside cell

smooth ER

no attached ribosomes, synthesizes lipids and carbs

rough ER

ribosomes bound to membranes, modifies and packages newly synthesized proteins

ribosomes

RNA and proteins; fixed bound to rough ER, free scattered in cytoplasm; synthesizes proteins

cytoskeleton

proteins organized in microfilaments or tubules; strengthen and supports cell, move cell structures and materials

mitochondrion

double membrane with inner membrane folds enclosing important metabolic enzymes; produces 95% of cell’s ATP

plasma membrane

separates cell contents (cytoplasm) from extracellular fluid; selectively permeable

glycocalyx

formed by superficial membrane carbs; important in cell recognition, binds to extracellular structures, and lubricates cell surface

integral proteins

part of membrane structure and can’t be removed without damaging/destroying membrane. may contain pores.

phospholipid bilayer

aka the plasma membrane. phospholipid molecules form two layers; bind with hydrophilic/phobic parts on surface/inside, respectively. hydrophobic layer in center of membrane isolates cytoplasm from extracellular fluid.

microfilaments

in bundles beneath cell membrane/cytoplasm; found in most cells; provide strength, alter cell-shape, etc

intermediate filaments

found in most cells, specifically the cytoplasm; provide strength, move materials through cytoplasm

microtubules

found in most cells in cytoplasm radiating away from centriole pair; provide strength, move organelles, major components of centrioles/cilia

thick filaments

skeletal/cardiac muscle cells in cytoplasm; interact with actin microfilaments to contract muscles

centrioles (organelles)

nine groups of microtubule triples form a short cylinder, found in pairs near nucleus; organize microtubules to move chromosomes during mitosis

cilia

nine groups of long microtubule doublets form a cylinder around central pair, found at cell surface; beat rhythmically to move fluids or secretions across cell surface

cristae

increases surface area exposed to matrix of mitochondrion

cisternae

flattened sheets/chambers formed by ER

matrix

liquid enclosed by inner membrane within mitochondrion

aerobic metabolism

aka cellular respiration, the process through which ATP is produced. in mitochondria, it produces 95% of the cell’s necessary ATP to live.

membrane renewal vesicles

add to the surface area of the plasma membrane

secretory vesicles

contain secretions (hormones or enzymes) that will be discharged from cell

transport vesicles

deliver some proteins and glycoproteins that were synthesized in RER to golgi apparatus

nucleus

control center for cellular processes

autolysis

destructive process in which digestive enzymes become active and attack cytoplasm

nuclear envelope

surrounds nucleus and keeps it separate from cytoplasm; double layered

nuclear pores

account for ~10% of surface of nucleus; passageways that permit chemical comms between nucleus and cytosol. (proteins and DNA cannot freely cross nuclear envelope.)

nucleoplasm

fluid contents of nucleus, also contains ions, enzymes, RNA, and DNA

nucleolus

nuclear organelle that synthesizes ribosomal RNA and assembles ribosomes. most prominent in cells that manufacture a lot of proteins (e.g. liver, nerve, muscle)

chromosomes

supercoiled DNA

chromatin

loosely coiled, fine filaments

centromere

holds chromosomes together

genetic code

chemical “language” used

nitrogenous bases

adenine, thymine, cytosine, guanine

gene

functional unit of heredity, contains all DNA needed to produce certain proteins

messenger RNA

single stranded RNA; contains complementary codons

codon

series of three RNA nucleotides

triplet

sequence of three nitrogenous bases along DNA strand that codes for an amino acid

transcription

takes place in nucleus; dna is copied into mRNA

translation

occurs in cytoplasm on ribosomes. mRNA’s genetic code is followed to build a chain of amino acids into a protein molecule; ribosomes detach at end

tRNA

ferry amino acids to ribosome. each contains nucleotide sequence known as anticodon

cell division

responsible for increase in cell number

apoptosis

cell suicide

(programmed cell death)

mitosis

produces two daughter cells, which each contain 46 chromosomes

meiosis

produces sex cells, which contain only 23 chromosomes

name the phase

interphase. performs normal functions, not actively engaged in division

daughter cells

produced by division of single cell

dna replication

begins when enzymes unwind strands and disrupt H bonds between bases

dna polymerase

bind to exposed nitrogen base; promotes bonding between nitrogenous bases and nucleotides; link nucleotides by covalent bonds

cytokinesis

cell divorce (aw sad)

(process that divides the cytoplasm of two daughter cells)

name the phase

prophase. centrioles replicate, spindle fibers connect centriole pairs, chromatid forms

name the phase

metaphase. chromatids move to metaphase plate and align

name the phase

anaphase. centromere of each chromatid pair splits and chromatids separate

name the phase

telophase. nuclear membranes reform, nuclei enlarge, and chromosomes uncoil from chromatin state

cleavage furrow

gap between two cells in telophase; constricted cytoplasm along metaphase plate

tumor

mass produced by abnormal cell growth/division

benign tumor

not life-threatening, doesn’t metastasize

malignant tumor

bad bad bad. life-threatening, DOES metastasize, divide rapidly and release chemicals that stimulate blood vessel growth. malignant cells may no longer perform original functions (or just perform them in an abnormal way)

invasion

process of when tumor starts spreading outside of isolated mass of cells and migrates to surrounding tissue

metastasis

migration to surrounding tissue

cancer

usually begins with single abnormal cell. cancer cells don’t use energy efficiently, and may cause death when they kill/replace healthy cells, compress vital organs, or deprive normal tissues of essential nutrients

permeability

property that determines which substances can enter/leave cytoplasm

freely permeable membranes

allow any substance to pass without difficulty

selectively permeable membranes

e.g. the plasma membrane; allow passage of some materials and restrict others

impermeable membranes

you shall not pass

(nothing can pass through. sorry, had to sneak in a LoTR reference.)

diffusion

movement driven by concentration differences; passive

facilitated diffusion (carrier-mediated transport)

may be active or passive; integral carrier proteins assist passage of specific substances

vesicular transport

intracellular vesicles form to transport substances. always active.

osmosis

diffusion of water across membrane

pinocytosis

vesicles form and bring fluids/small molecules into cell; often called “cell drinking”

receptor-mediated endocytosis

target molecules bind to receptor proteins and trigger vesicle formation

phagocytosis

large particles brought into cell by cytoplasmic extensions called pseudopodia; only phagocytes or macrophages perform phagocytosis

exocytosis

intracellular vesicles fuse with plasma membrane to release fluids/solids

epithelial tissue

layer of cells that forms a barrier w specific properties; covers every exposed body surface, lines organs/blood vessels, and surrounds internal cavities; produces glandular secretions (?)

connective tissue

contain specialized cells and extracellular matrix (which contains protein fibers and a liquid known as ground substance); fills internal spaces, provides structural support, stores energy

muscle tissue

have ability to contract forcefully. three types:

• skeletal muscle tissue, which is attached to skeleton and moves/stabilizes position of internal organs/bones w contractions

• cardiac muscle tissue, which is only found in the heart. contractions propel blood through vessels.

• smooth muscle tissue, which is found in walls of blood vessels, glands, and along all tracts

neural tissue

specialized to carry info from one place to another. two basic types:

• nerve cells (neurons), which transmit info through electric impulses

• supporting cells (neuroglia, or just glia) which protect neurons

can be divided into central nervous system (brain and spinal cord) and the peripheral nervous system (all other nerves not in brain/spinal cord)

histology

study of tissue

circadian rhythm

repeats roughly every 24 hours; dictates certain physiological functions (cortisol release before waking up, high temperature before bed); influenced by period gene and PER protein

PER protein

builds up during the day and degrades at night, induces sleepiness (?); when it’s bound with TIM, it can enter the nucleus; DBT protein delays accumulation; negative feedback loop

risks of disrupted circadian rhythm?

cancer, disrupted metabolic pathways, other diseases = increased rates

anaerobic respiration

atp creation without oxygen. results in buildup of lactic acid + fermentation

endogenous

occurs inside a cell

exogenous

occurs outside a cell

glycolysis

metabolic pathway that converts glucose into pyruvate; does not produce the most ATP