A&P - test 2

helicase

unzips the DNA, breaks through the H bonds; the unzipper

RNA primase

starts the replication process; the initializer

DNA polymerase

brings in bases for pairing; the builder; synthesizes the leading and lagging strand simultaneously

DNA ligase

glues the segments; the gluer

semiconservative replication

each new DNA molecule consists of one new strand and one old strand

Okazaki fragments

segments of the lagging strand that get glued together by ligase

leading strand

built continuously in the same direction of helicase

lagging strand

built discontinuously

DNA replication

s phase, in nucleus, ends with two identical daughter DNA

replication fork

point where strands separate

replication bubble

active area of replication

transcription

nucleus, DNA to RNA

mRNA

gets the code that is on the DNA to leave the nucleus, contains the codon

codon

triplet of nucleotides that codes for a particular amino acid

DNA

the master blueprint that holds the code for protein synthesis

gene

a segment of DNA that holds the code for one polypeptide

rRNA

structural component of ribosomes, where protein synthesis occurs; helps translate message from mRNA into polypeptide

tRNA

carrier of amino acids, contain the anticodon, used in translation

translation

decoding of a mRNA message into a polypeptide chain

initiation

RNA polymerase separates DNA strands

elongation

RNA polymerase adds complementary nucleotides to growing mRNA matching sequence of based on DNA template strand; DNA RNA hybrid

termination

transcription stops when RNA polymerase reaches specific terminal signal code

amino acids

20

redundancy

helps protect against transcription errors

ribosomes

coordinate coupling of mRNA and tRNA

protein release factor

binds to stop codon causing water to be added to the chain instead of another tRNA; releases the polypeptide chain as separates ribosomal subunits and degradation of mRNA; processed into functional 3d protein

melanin

pigment made by melanocytes \n sun exposure stimulates production \n redish yellow or brownish black \n freckles and pigmented moles \n a chemical barrier against radiation damage

carotene

yellow to orange pigment \n most obvious in palms and soles \n accumulate in stratum corneum and hypodermis \n can be converted to vitamin A for vision and epidermal health

hemoglobin

pinkish hue of fair skin is due to lower level of melanin

leathery skin

elastic fibers clump up

excessive sun exposure

can depress immune system and cause alterations in DNA that may lead to skin cancer

UV light

destroys folic acid which is necessary for DNA synthesis; especially dangerous for developing embryos

cyanosis

blue; low oxygenation of hemoglobin

erythema

redness; fever, HTN, inflammation, allergy

pallor

blanching; anemia, low bp, fear, anger

jaundice

yellow; liver disorders

skin function

protection, body temp, cutaneous sensations, metabolism, blood reservoir, excretion

chemical barrier

sweat, sebum, cells

sweat

contains antimicrobial proteins

sebum and defensins

kill bacteria

cells

create antimicrobial defensin

acid mantle

low pH of skin retards bacterial multiplication

physical

flat, dead, keratinized cells of stratum corneum, surrounded by glycolipids, block most water and water soluble substances; some chemicals have limited penetration of skin

epidermis

contains phagocytic cells

dendritic cells

of epidermis engulf foreign antigens and present to wbc activating the immune response

dermis

contains macrophages that activate immune system

DNA (skin)

can absorb harmful radiation, converting it to harmless heat

Pacinian corpuscles

deep touch receptors

Meissners corpuscles

sensitive touch receptors in the dermis

excretion

skin can secrete limited amounts of N waste, ammonia, urea, uric acid

benign

not cancerous

metastasize

to spread

skin cancer risk factors

overexposure to UV radiation or frequent irritation of skin

basal cell carcinoma

least malignant most common \n stratum basale cells proliferate and slowly invade dermis and hypo \n cured by surgical excision

squamous cell carcinoma

second most common; can metastasize \n keratinocytes of spinosum \n scaly reddened papulae on scalp, ears, lower lip, or hands \n treated by radiation or removed surgically

melanoma

melanoma

cancer of melanocytes; most dangerous because it is highly metastatic and resistant to chemo \n treated with surgical excision accompanied by immunotherapy

A

two sides of pigmented area dont match

B

exhibits indentations

C

several colors

D

larger than 6mm

burns

damage caused by denaturation of proteins which destroy cells \n immediate threat is dehydration and electrolyte imbalance

dehydration and electrolyte imbalance

leads to renal shut down and circulatory shock

first degree

first degree

epidermis only \n localized redness, edema, pain

second degree

epidermis and dermis \n blisters \n partial thickness

third degree

full thickness \n skin color turns grey-white, cherry red, or black \n no edema or pain because nerve endings are destroyed \n skin grafts

lanugo coat

delicate hairs in 5th and 6th month

vernix caseosa

sebaceous secretion that protects skin of fetus while in watery amniotic fluid

infancy to adult

\n skin thickens and accumulates more subcutaneous fat; glands are active which lead to acne \n optimal in 20 and 30 \n scaling and dermatitis

aging skin

thin, dry and itchy due to dec gland activity \n fat and elasticity dec leading to cold intolerance \n inc risk of cancer bc dec melanocytes and dendritic cells \n hair thinning

delay aging

UV protection, good nutrition, lots of fluids, good hygiene

skeletal cartilage

made of highly resilient molded cartilage tissue that consists primarily of water; no bv or nerves

perichondrium

layer of dense connective tissue surrounding cartilage like a girdle; has bv

hyaline

provides support, flexibility, and resilience \n most abundant with collagen fibers only \n covers area of bone that forms moveable joint

elastic

similar to hyaline but elastic fibers \n external ear and epiglottis

fibrocartilage

thick collagen fibers \n great tensile strength \n menisci of knee and vertebral discs

fibroblasts

outer layer produces collagenous fibers that provide the skin with structure and strength for bones; contains bv

inner chondrogenic

outer layer that has chondroblasts for the formation of new cartilage

appositional growth

outside; forming cells in perichondrium and secretes matrix against exterior face of existing cartilage

interstitial growth

inside; lacuna divide within and secrete new matrix expanding cartilage

calcification of cartilage

occurs during normal bone growth in youth but can also occur in old age; not the same as bone

function of bone

support, protect, movement, mineral and growth factor storage, blood cell formation, triglyceride storage, hormone production

axial

long axis of bone \n skull, vertebral column, ribcage

appendicular

bones of upper and lower limbs \n girdles attaching limbs to axial skeleton

compact bone

dense outer layer on every bone that appears smooth and solid

spongy bone

made of honeycomb of small needle like flat pieces of bone called trabeculae; filled with red bone marrow

structure of short, irregular, and flat

consists of thin plates of spongy covered by compact

periosteum

covers outside of compact bone \n white, double layered membrane

endosteum

covers inside of compact bone \n delicate connective tissue membrane \n covers trabeculae \n lines canals \n contains osteogenic cells that con differentiate

trabeculae

interconnecting rods or plates of bone \n functional unit of spongy bone \n irregularly arranged lamella \n no osteon \n oriented along stress lines

diaphysis

shaft; compact \n surround medullary cavity

medullary cavity

filled with yellow bone marrow in adults

epiphysis

end; spongy \n compact exterior \n articular over joint

epiphyseal plate

growth plate

epiphyseal line

bone stops growing in length between diaphysis and epiphysis

fibrous mem (periosteum)

outer with dense irregular connective tissue with Sharpeys fibers

sharpeys fibers

in fibrous outer membrane that secure bone to matrix

osteogenic mem (periosteum)

inner abutting bone and contains primitive osteogenic stem cells that give rise to most all bone cells \n contains many nerve fibers and bv that continue on to the shaft through nutrient foramen openings

red marrow in adults

trabecular cavity heads of femur and humerus and flat bones like hip and sternum

red marrow in newborns

medullary cavities and all spongy bone contain red marrow

osteogenic cells

stem cells \n mitotically active in peri and endosteum \n differentiate into blasts or bone lining \n some remain