MCB 32 Unit 1

Modules 1-8

ectotherm

body temperature flucuates with environment; cold-blooded

endoterm

body works very hard to maintain body temp; warm-blooded; we stay cool when it’s hot out by sweating, ie.

negative feedback loop

brings our body back to homeostasis b/c a variable/stimulus triggers a counteracting response, returns us to set point

type 1 diabetes

pancreas isn’t working correctly, insluin not produced, so cells can’t take in glucose

positive feedback loop examples

childirth and ovulation

negative feedback loop examples

stable body temperature and blood glucose regulation

organ systems

made up of diff. organs and tissues working together for one major function (endocrine, cardiovascular, etc.)

external environment

parts of the body that are directly connected to the outside

internal environment

opposite of external environment; materials enter or are absorbed by cells

if a system has a mixture of internal and external components (some organs in external envir, some in internal), is the system as a collective an internal or external system?

external

internal envir. organ systems

endocrine, nervous, cardiovascular, and muscular

total body water

all the water contained in the body’s internal compartments or envir. (doesn’t include water in digestive track or other external components)

intracellular fluid (ICF)

water inside of cells, 2/3 of total body water

extracellular fluid, ECF

fluid outside the cells (but still in internal envir.); includes plasma, interstital fluid, and interstital space

what is plasma?

ECF in blood

what is interstitial fluid?

ECF not in blood that surrounds cells

what is interstitial space?

area outside of cells; physical location where interstitial fluid (kind of ECF) is located

which organ system regulates all the organs in our body?

nervous

which organ system regulates all the tissues in our body?

endocrine

what organ system helps move materials from 1 part of the body to another?

cardiovascular

mass balance

the body has to balance what comes in and what leaves

input

intake thru intestines, lungs, and skin; metabolic production

output

excretion by kidneys, liver, lungs and skin; metabolism of a new substance

law of mass balance

mass balance = (existing body load + intake or metabolic production) - excretion or metabolic removal

homeostasis

ability of organisms to keep a relatively stable internal environment in face of changing external conditions

sensors

sense surroundings; measures or interprets the stimulus

integrating center

compares sensor information to set point

effector

an object that acts out on information relayed to it by integrating center; causes a response

response

what happens (the action) to come back to homeostasis; opposes set point in positive feedback, brings us back to it in negative feedback

sensors in body temperature regulation

thermoreceptors in skin and hypothalamus

integrating center in body temp. regulation

hypothalamus

effector in body temp. regulation

sweat glands

heat exhaustion

excessive sweating as the body tries to cool down; occurs when we get too hot

heat stroke

body gets so hot that it can’t respond properly; we stop sweating to cool down because body is no longer trying to cool down

monomer

building block that makes up something larger

covalent bonding

2 non-metals sharing valence electrons

ionic bonding

1 metal and non-metal, non-metal takes electron from metal

hydrogen bonding

formed between the partial positive and negative charges between two molecules

cohesion

water’s ability to stick to itself

adhesion

water’s ability to stick to other substances

biomolecules

synthesized by living organisms and contain carbon atoms; many are polymers made up of repeating monomers

carbohydrate functions

broken down for energy, added to proteins and lipids to change their function, and involved in cell to cell recognition

list of biomolecules

carbohydrates, lipids, proteins, and nucleic acids

steroids

4 carbon rings (4 carbon structures) synthesized from cholesterol

fatty acids

long hydrocarbon chains

triglycerides

fats made up of glycerol and 3 fatty acids; store energy in body

phosholipids

polar phosphate group and nonpolar tail make them amphiphilic; R group determines identity (can be charged, polar, or nonpolar)

peptide

fewer than 50 amino acids connected together

how many amino acids are in protein?

greater than or equal to 50

protein functions

act as chemical messengers, move molecules across cell membrane, provide structural support for cells, act as channels in cells, enzymes, and much more

examples of lipids

triglycerides, steroids, and phospholipids

lipid functions

glycerol and fatty acid building blocks; source of long-term energy storage; hormones

which biomolecules are polar?

carbs, proteins, and nucleic acids

which biomolecules are non-polar?

lipids

induced fit

active site on an enzyme can change shape to bind to substrate

true or false: enzymes can only build up substrates?

FALSE; enzymes can both build up AND break down substrates

-ase

suffix for enzymes

metabolism

sum of chemical reactions occurring in the body

anabolic reaction (endergonic)

product of larger molecules; energy is a reactant

catabolic reactions (exergonic)

breakdown of larger molecules into their subunits; energy is a product in the form of heat or it energy that can be harnessed by the cell (as ATP) to power anabolic reactions

activation energy

intermediate step that’s high in energy, higher than reactant AND product energies; stops catabolic reactions from occurring spontaneously

enzymes function by…

lowering activation energy (Ea)

affinity

how complementary the substrate and enzyme are, how attracted they are to each other

increased specificity of enzyme and substrate leads to _____ affinity

increased

how do enzymes decrease activation energy?

by bringing reactants together in same space and stabilizing high energy intermediate stage of reaction, lowering req. energy for intermediate step

allosteric regulation

small molecules that bind to enzymes outside active site; causes enzyme to change shape and affinity for substrates; powered by hydrogen bonds

covalent modification

changes affinity using another enzyme via phosphorylation; catalyzes covalent bond formation; can occur at either the active site or a site outside of active site

phosphorylation

covalent modification; a kinase, PKA (protein kinase A in liver cells), adds a phosphate group to an enzyme

how do you regulate enzymes long-term?

by either synthesizing more enzymes or destroying them

what activates phosphorylation?

cylic AMP, or cAMP, binding to PKA

albinism reaction pathway

single amino acid in tyrosinase is changed, which changes its ability to bind to substrate L-tyrosine

when would you want to synthesize cAMP in liver cells?

when we need glucose for energy (catabolic reaction, glycogen to glucose), because glycogen synthase (substrate) binds to PKA AFTER cAMP binds to PKA

tissue

collection of cells with related functions

organs

set of tissues that carry out specific functions

epithelial tissue

a continuous, sheet-like layer of cells; lines inside of tubes (intenstinal tubes, blood vessels, etc.)

extracellular matrix

area outside of the cell that’s made of proteins and sugars secreted by cell

lumen

center of a tube in the body

tight junctions

hold adjacent epithelial cells together; made from transmembrane proteins; prevent molecules from passing in between cells

epithelial tissue function

either separates different body fluids or a body fluid from outside (epidermins in skin, protects lungs from external environment, etc.)

which cell type forms glands?

epithelial

exocrine gland

secrete chemicals into external environment (sweat glands)

endocrine glands

secrete hormones into blood stream

connective tissue function

provides structural support

connective tissue examples

fat, bones, tendons, and blood

connective tissue

extensive extracellular matrix with scattered cells; cells not directly attached

muscle tissue types

skeletal, cardiac, and smooth

skeletal muscle

control bones, can be voluntarily controlled

cardiac muscle

makes the heart contract

smooth muscle

line blood vessels and digestive tract

which tissue type can contract force?

muscle

nervous tissue

consists of neurons and their support cells (glia); neurons communicate to each other with electrical signals and use chemical signals for external communication

plasma membrane

surrounds cells; made of a phospholipid bilayer, proteins, sugars, and cholesterol

nucleus

contains genetic info in form of chromatin (DNA and its associated proteins); inside nucleus, transcription occurs

transcription

genes are copied into mRNA inside nucleus

translation

mRNA is coded into proteins by ribosomes

cytoplasm

inside of a cell (sans nucleus); made up of cytosol and organelles, or structures that carry out a particular function (like the Golgi apparatus, ER, lysosomes, and mitochondria)

endoplasmic reticulum (ER)

network of membranes surrounding the nucleus; includes rough ER and smooth ER

rough ER

has ribosomes, which also are free-floating in cytoplasm; ribosomes responsible for protein synthesis

smooth ER

no ribosomes, synthesizes lipids

exocytosis

secretory vesicles carry proteins to plasma membrane, where vesicle and plasma membrane fuse; this releases secretory vesicle contents (usually polypeptides)