chapter 3: cellular levels of organization

the _____ is the basic, living, structural, and functional unit of the body

the _____ is the basic, living, structural, and functional unit of the body

cell

define cytology

study of cell structure

define cell physiology

study of cell function

what are the 3 principle parts of the cell?

plasma membrane, cytoplasm, nucleus

describe the plasma membrane & fluid mosaic model

plasma membrane is a flexible, sturdy barrier surrounding the cytoplasm. the fluid mosaic model is a gelatinous [phospholipids] layer with floating proteins

the plasma membrane is __% lipid & __% protein held together by ____ bonds.

• lipid is barrier to entry/exit of polar substances. proteins regulate traffic.

• there are 50 lipids for every protein molecule. why?

50. 50. hydrogen. because lipids are smaller than proteins so there needs to be more of them to keep up the ratio

water moves freely through protein covered tubes in the plasma membrane called _____ _____

polar pores

what are 3 examples of amphipathic lipids?

phospholipids, cholesterol, glycolipids

phospholipids have polar () & nonpolar () parts

charged. uncharged

cholesterol is [strongly/weakly/moderately?] amphipathic.

• they are interspersed among other lipids

weakly

what type of amphipathic lipid appears only in the membrane layer which faces the ECF (have a carbohydrate head)?

glycolipids

• define integral membrane proteins

  • what happens if it’s removed?

• define peripheral membrane proteins

  • what happens if it’s removed?

extend into/across entire lipid bilayer. destroys the membrane. found at inner OR outer surface of membrane. doesn’t destroy the membrane

what are the 6 plasma membrane functions? explain each.

1. pores (allow specific ions to move through)

2. transporters (active transporters)

3. receptors (molecule binds to it & opens a gate)

4. enzymes

5. cell ID markers (distinguishes cell from bacteria; self vs non-self)

6. linkers (connectors)

what are the 3 overall plasma membrane functions?

communication, electrochemical gradient, selective permeability

plasma membranes are selectively permeable. what does this mean?

some things can pass through & others can’t

the plasma membrane is [always/sometimes/never?] permeable to water

always

transmembrane proteins act as _____ & [increase/decrease?] the permeability

channels/transporters. increase

what are 4 examples of passive processes for transport across the plasma membrane?

diffusion, osmosis, facilitated diffusion, filtration

what are active processes in regards to transport across the plasma membrane?

requires cellular energy (active transport uses ATP). vesicle transport via exocytosis/endocytosis

mediated transport across the plasma membrane: needs transporter proteins

answer: :)

:)

define diffusion

movement of a substance from high to low concentration. goal is equilibrium

where does diffusion occur in the body?

everywhere

what are 3 factors that effect diffusion?

molecule size (bigger=slower), KE (high heat=speeds up), concentration gradient (not at equilibrium=speeds up)

diffusion is caused by brownian movement. what does this mean?

molecular collisions

according to brownian movement, molecules hit each other (collide) less when they…

spread out and reach equilibrium

what are 5 examples of things that diffuse THROUGH the lipid bilayer (ie are nonpolar & hydrophobic)

water, respiratory gases (CO2, O2), some lipids, small alcohols, vitamins a, d, e, k

diffusion through membrane channels:

• most are _____ channels

  • small, inorganic ions which are hydrophilic

• _____: water

• ion channels are _____ & specific & may be gated or open all the time

ion. aquaporins. selective

define osmosis & osmotic pressure

osmosis (diffusion of water across a selectively permeable membrane. osmotic pressure (proportional to the concentration of the solute particles that can’t cross the membrane

osmosis/osmotic pressure experiment:

a. start of experiment: water on one side, then membrane, then high solute concentration on other side… water levels even on both sides

b. equilibrium: movement due to hydrostatic pressure… water level higher on side with high solute concentration

c. restoring starting conditions: applied pressure on side with high solute concentration = osmotic pressure to make volumes equal on both sides of membrane

answer: :)

:)

describe RBCs in isotonic, hypotonic, & hypertonic solutions.

1. isotonic: equally salty inside & outside of cell. normal cell shape.

2. hypotonic: inside of cell is saltier than water. more water outside the cell → water flows into cell → cell pops (HEMOLYSIS)

3. hypertonic: more water inside cell than outside of cell → water moves out of cell → leaves RBC with less water than needed → cell shrivels (CRENATION)

water movement in cells (isotonic/hypotonic/hypertonic) is caused by …?

purity of the water

define filtration

movement of a substance across a membrane due to fluid pressure differences

where does filtration occur?

everywhere with blood

define facilitated diffusion

solute binds to specific transporter on one side of membrane & released on other side after transporter undergoes conformational change (doesn’t require energy)

what 2 types of substances does facilitated diffusion work with?

small molecules & vitamins

the rate of facilitated diffusion depends on what 2 things?

concentration gradient & number of transporter proteins (lower number = slower diffusion)

define active transport

requires ATP & transporter proteins. movement across concentration gradient

what types of atoms are moved in active transport?

charged atoms

cystic fibrosis:

• genetic

• produces abnormal …

• affects which 4 systems?

• genetic engineering failed

• triple-drug can _____ life by 90%. treats symptoms but doesn’t cure

• is there a cure?

• what is a method of treatment that is alternative medicine that has been accepted by mainstream medicine?

• _____ production interferes with gas exchange

chloride ion transporter. respiratory, digestive, urinary, reproductive. improve. no. type of massage on back to loosen fluid in lungs. mucous

what is a vesicle & what are 2 ways it can work?

small membranous sac formed by budding off from an existing membrane. endocytosis & exocytosis

• define endocytosis

  • define phagocytosis

  • define pinocytosis

• define exocytosis & the process

bringing something into cell. cell eating by macrophages & WBCs; binds to receptor protein. cell drinking; no receptor proteins. release something from cell; vesicles form inside cell, fuse to membrane, release contents (digestive enzymes, hormones, neurotransmitters, waste products), replace cell membrane lost by endocytosis

define cytosol

• location?

• structure?

• function?

semifluid part of cytoplasm. inside cell membrane, NOT including organelles. semifluid. medium for metabolic reactions

define cytoskeleton

protein filaments throughout cytosol. functions as cell support and shape

define centrosomes, what they contain, how they work, how they move chromosomes, etc

dense areas of cytoplasm. contain centrioles - paired cylinders at right angles. centers for organizing microtubules in interphase cells. mitotic spindle during cell division. spindle fibers move chromosomes from metaphase plate to poles

describe cilia

numerous, short, hair-like projections from surface of cell membrane. move material over surface of cell

describe flagella

single, very long. cellular movement. only human example - sperm tail

ribosomes made of what 2 things?

• ribosomes occur singly or in _____

• ribosomes free in cytoplasm OR …

• purpose: protein synthesis

rrna & proteins. clusters. attached to ER (smooth ER)

large & small ribosomal subunits:

• made where?

• assembled where?

nucleolus, cytoplasm

does the smooth or rough ER have ribosomes attached?

rough

ER:

• network of …, like a cave system

• purpose: to do what 3 things?

• _____ chemicals

• EX: when chemicals build up (like urea), ER detoxifies it

flattened sacs and tubules. transport, synthesis, storage of molecules. detoxify

drug detoxification happens in the _____.

• one of the functions of the smooth ER is to _____ drugs

• what happens due to repeated exposure to certain drugs?

liver. detoxify. produces changes to smooth ER in the liver; results in tolerance to drugs

golgi complex:

• made of what 2 materials?

• shape?

• 3 purposes?

• what are secretory vesicles?

protein & lipids. flattened sacs. processing, sorting, delivery. release the product

where do lysosomes initially form?

golgi

lysosomes contain powerful _____ _____

digestive enzymes

4 functions lysosomes?

intracellular digestion, autophagy (worn out organelles), autolysis, extracellular digestion

describe tay-sachs disorder

affects children of eastern european jewish descent. seizures, muscle rigidity, blindness, dead before 5. genetic disorder caused by absence of a lysosomal enzyme (hexosaminidase A). this enzyme normally breaks down glycolipid commonly found in nerves (destruction of nerves in nervous system because of lack of enzyme)

how did tay-sachs disorder become so prevalent in the eastern european jewish descent people?

bottleneck effect. many Jews killed, and those left had unusually high rate of tay-sachs. then they passed it down/

define peroxisomes

similar in structure to lysosomes. smaller. contain enzymes that oxidize organic substances

what do proteosomes do?

destroy faulty proteins

mitochondria:

• _____ membrane bound

• inner membrane folds are called _____

• site of _____ production

• what is special about their DNA?

double. cristae. ATP. mitochondria have their own DNA and self replicate. this DNA is inherited from the mother. fathers only contribute sperm, & the mother’s egg contains the mitochondrial DNA

mitochondrial myopathies:

• inherited _____ disorders

• resulting from…

• muscles become _____ & _____ easily

  • ^ how?

muscle. faulty mitochondrial genes. weak & fatigued. less ATP production = less endurance

define cell inclusions

large non-organelles found in cytoplasm

what are 3 examples of cell inclusions? explain each.

melanin (protect from UV & cancer/melanoma. protect from reflection in eyes), glycogen (long chain carbohydrate stored in muscles. readily digestible), triglycerides (1 glycerol, 3 fatty acids)

the nucleus is usually the most _____ feature of a cell

prominent

do RBC’s have a nucleus? why/why not?

• most cells have a nucleus

• some skeletal cells have many nuclei

no. they have a shorter lifespan because of it. no nucleus because it has one job: to carry oxygen around the body. the shape of the RBC blocks nucleus to maximize oxygen

a wiffle ball can be a representation of what part of the cell?

nuclear envelope with nuclear pores

define nucleoli deals with _____ _____. this is only observed in non-[_?] cells

ribosome synthesis. dividing

where is the nucleoli located?

inside nuclear envelope

chromosomes

• long & coiled dna

• how are genes arranged?

• what do histone proteins do?

• how many chromosomes do we have?

single file along length of dna. organize folding & coiling of DNA. 46; 23 pairs

chromosomes are VERY HIGHLY _____!

coiled

what is chromatin?

• describe the 2 types of chromatin?

DNA not as distinct chromosomes. heterochromatin (regulates turning off/on genes; more condensed; doesn’t contain gene; not transcribed). euchromatin (active chromatin; contains DNA; transcribed into RNA)

describe the sense & antisense strands.

sense (coding): not copies

antisense (template): template for mRNA

describe the 4 significant parts of a gene/dna strand

promoter (near beginning of gene where RNA polymerase attaches). introns (don’t code for proteins; later removed). exons (don’t code for parts of proteins). terminator (detachment of RNA polymerase)

describe genetics vs genomics

genetics is how things are inherited. genomics is more broad & is about relationships between the genome & functions of an organism

protein synthesis involves what 2 things?

transcription & translation

briefly describe dna replication, transcription, & translation

1. dna replication: making copy of dna inside nucleus

2. transc: info transcribed from dna strand to mrna

3. transl: construction of protein using mrna instructions

describe mrna & trna

1. mrna: instructions

2. trna: carries amino acid to ribosome

genetic engineering/therapy:

• insert new genes into existing _____.

• used now in bacteria to produce what 4 things?

DNA. hGH, insulin (get insulin from bacteria with human gene inserted that make insulin), interferon (antivviral; blood cell production), erythroboietin

describe CRISPR

enzyme system used to cut out gene and replace with another gene

what term does this describe: sequence of events where a cell duplicates is its contents & divides in 2

cell cycle

how long does the cell cycle normally last?

1-2 days

describe the phases of the cell cycle

1. G0: prep for cell division

2. S: DNA replication (trying to go from 46 to 92 chromosomes so that when the cell splits, each cell gets 46 chromosomes (in mitosis)).

3. G2: prep for cell division

4. M: nuclear division (mitosis/meiosis) & cytokinesis (cytoplasm)

describe prophase, metaphase, anaphase, & telophase

answer: :)

:)

what’s the product of mitosis?

2 identical daughter cells (clones)

what are 3 possible destinies of a cell?

remain alive & functioning without dividing (neuron). grow & divide (most cells). die.

_____ _____ _____ (MPF) induces cell division

maturation promoting factor

describe apoptosis

cell death. triggered by outside (chemicals) or inside, pr “cell suicide” (when too old)

define necrosis

a pathological cell death due to an injury. cut off blood supply

describe aging

normal process resulting in observable changes in structure & function, increased vulnerability to stress and disease. study: geriatrics

what are the 4 theories of aging? describe each.

1. glycosylation: glucose added to proteins forming cross linkages, which interfere with normal cell functioning & loss of elasticity

2. genetic programming: heart, skeletal muscles, nerves always in G0. most cells divide a max of 50x

3. free radical theory: oxidative damage (steal electrons), damage lipids, proteins, nucleic acids

4. autoimmunity: changes in cell ID markers. person’s own cells attached by their own antibodies

define progeria

genetic; telomeres very short

define werner’s syndrome

inherited; premature aging

define cancer

uncontrolled cell proliferation

who studies cancer/tumors?

oncologists

tumors are also called _____

neoplasm

what is the difference between benign & malignant tumors?

benign can still kill you, but less so than malignant. malignant metastasizes

what are the 5 types of cancer? define each.

1. carcinoma: epithelial

2. sarcoma: muscle/connective

3. myeloma: bone marrow

4. leukemia: blood forming organs

5. lymphoma: lymph nodes

define hyperplasia

cancer growth

define metastasis

spread of cancer

define angiogenesis

growth of new blood vessels