KNES 323 Midterm Review

state of balance in the body and is maintained by the body’s regulatory processes

homeostasis

how does the body maintain homeostasis

• detects abnormality

• use and processes this information with other relevant information

• make the needed adjustments

normal range for a given system; monitored by the control centre for that particular system

set point

·       24 hour day night/cycles, allowing organisms to adapt to an ever changing environment

·       Major regulatory factor for most physiological activities – keeps everything in check

circadian rhythm

when cortisol levels are high during the time of sleep, this leads to what kind of disorder?

insomnia

local controls that are in the organ

intrinsic controls

what is an example of intrinsic controls in heart rate?

the SA node

regulatory controls that are initiated by the nervous and endocrine systems outside of the organ

extrinsic controls

what are examples of extrinsic controls in heart rate?

the vagus nerve - which decreases heart rate

sympathetic nerve - which increases heart rate

and adrenaline - which increases heart rate

feedback loops respond to what?

respond to change

what are the basic components of feedback loops?

• stimulus

• controlled condition

• receptors

• control centre

• effectors

• response

• this feedback loop opposes initial change

negative feedback loop

in a negative feedback loop, what is its main goal and what are its components/what do these components do?

• main goal: keep internal environments stable

• components: sensor, control center and effector

• sensor: monitors magnitude and controlled variable

• control center: compares sensor’s input with set point

• effector: makes a response to produce desired effect

explain the negative feedback loop of body temperature regulation

sweat glands have a negative feedback when it comes to the stimulus of above normal body temperature, causing the body temperature to decrease and go back to normal. because the body temperature was straying away from normal range, a negative response loop kicks in to pull as back to set point.

this feedback loop reinforces stimulus until it creates a change in the body

ex: contractions during labor

positive feedback loop

response to anticipation of change

anticipates changes before they occur to change production

primes the body for the changes that will occur

feedforward loops

general term for derangement of abnormality of function

disorder

specific term for an illness that is characterized by a set of signs and symptoms

disease

what happens with the body’s ability to restore homeostasis when we age?

it progressively declines

what are the 4 main macromolecules?

carbohydrates, proteins, lipids and nucleic acids

long molecules made up of similar building blocks of smaller molecules

polymers

what type of polymers can be broken down through hydrolysis and which can be only broken down by lipolysis?

• carbohydrates, proteins and nucleic acids can be broken down by hydrolysis

• lipids can be broken down by lipolysis

simplest macromolecule

carbohydrates

simplest sugar and cannot be further broken down – readily used fuel source

monosaccharides

what are the dietary monosaccharides that are readily absorbed by the small intestines

glucose, fructose and galactose

naturally occurring sugar from fruits, aiding in glycolysis and replenishes liver glycogen stores

fructose

disaccharide formed by glucose + fructose

sucrose

disaccharide formed by glucose + galactose

lactose

disaccharide formed by glucose + glucose

maltose

most common dietary disaccharide; occurs naturally and is in most foods that have carbohydrates

sucrose

·      in beer, cereals, germinating seeds; not as common in western diet

maltose

what are the 4 main types of polysaccharides

starch, glycogen, cellulose and chitin

storage form of carbohydrates in plants

Starch

• a form of starch

• long, straight chains forming helical coils; these are tightly packed, therefore, less easier to breakdown

amylase

• a form of starch

• highly branched glucose chains; these are branched, therefore, easier to break down

amylopectin

storage form of carbohydrates in animals

glycogen

process of glycogen converting into glucose

glycogenolysis

most abundant naturally occurring polysaccharide in plant walls providing structural support; hard to break down as it has long straight chains

cellulose

in the exoskeleton of arthropods providing structural support, similar to cellulose due to its long straight chains

chitin

how many amino acids is required to make a protein

20

if an enzyme is not present, what happens to the processes?

it will occur slowly or not at all

what are the 2 main types of enzymes and what do they do?

o   Anabolic Enzymes: uses energy to build a more complex molecule

o   Catabolic Enzymes: releases energy as it breaks down their substrate

digestion of carbohydrates in mouth and small intestine

amylase

digestion of protein in stomach

pepsin

emulsification of fat in small intestine

lipase

digestion of protein in small intestine

trypsin

lipid steroids

estrogen and testosterone

what is a role of some proteins?

can act as receptors to detect concentrations of chemicals and send signals to respond

• transported via lipoproteins

• comes from a single glycerol molecule and 3 fatty acids

• 3 main types: fats, phospholipids and steroids

lipids

maximal number of hydrogen atoms; no double bonds and is solid at room temperature (rigid structure)

saturated fatty acids

one or more double bonds; liquid at room temperature (less rigid)

unsaturated fatty acids

when H atoms are opposite from each other

trans

when H atoms are on the same side

cis

major components of plasma membrane. composed of fatty acid chains attached to a glycerol backbone, has 2 acids and a phosphate group

phospholipids

negatively charged making the head polar/hydrophilic

phosphate group

uncharged, non polar and are hydrophobic

fatty acid tails

consists of 2 adjacent layers of phospholipids, forming a bilayer and acts as a semipermeable membrane

cell membrane

plays roles in reproduction, absorption, metabolism regulation and brain activity

• has a fused ring structure

• four linked carbon rings

• hydrophobic and insoluble in water

steroids

most common steroid that is mainly synthesized in the liver

·      precursor to: vitamin D, steroid hormones, synthesizing aldosterone (for osmoregulation), and the formation of cortisol (for metabolism)

cholesterol

what factors equal energy intake?

internal heat produced

external work

internal work

energy storage

what are the 3 states of energy balance?

• neutral

• positive

• negative

energy input = energy output – no change in body weight

neutral energy balance

energy input > energy output – body weight increases

• energy that isn’t used is stored as adipose

positive energy balance

energy input < energy output – body weight decreases

• body uses stored energy

negative energy balance

amount of energy we need to use, internally and externally, to perform a given task

• basically how fast and efficient we use energy

• is energy expenditure divided by unit of time

metabolic rate

minimum internal energy used in order to meet the basic physiological functions of our body

Basal Metabolic Rate (BMR)

what are the factors that influence metabolic rate?

thyroid hormone levels, sympathetic stimulation (priming the body to expend energy), exercise, daily activities, sex/gender, age

life sustaining chemical processes enabling organisms to convert stored chemical energy into energy for cellular processes

metabolism

when an enzyme is used to speed up a reaction, does the reactant and/or product change? what about the overall energy of the system?

none of these changes when an enzyme is used, an enzyme can only speed up a reaction by decreasing the activation energy. which means that the reactant, product and overall energy of the system remain the same

how many chemical reactions can each enzyme control and how does this affect the pathway?

each enzymes can only control one type of chemical reaction, so if an enzyme is not active, the entire pathway cannot occur

why are enzymes key to cell functionality?

they determine which chemical reactions a cell can produce and the rate at which it can do so

describe the process of how enzymes work on metabolism

·      Substrates enter the active site where the enzyme changes its shape so there is an induced fit

·      Substrates are held in by hydrogen and ionic bonds

·      The active site lowers the activation energy and speeds up the reaction

·      Substrates are then converted into products, which are then released to vacate the active sites for new substrates

chemical reaction that releases energy

Exothermic Reactions

chemical reaction that needs energy to continue

Endothermic Reactions

all of the chemical reactions that occur inside cells

cellular metabolism

·      inhibitor molecule is similar to a substrate that it binds to the enzyme’s active site, blocking it from binding – there is a competition to bind with the substrate

o   Cuts the rate of reaction in half – slower by half compared to a normal enzyme

competitive inhibition

·      inhibitor molecule binds to enzyme at the allosteric site – there is no competition as the substrate can still bind to the enzyme, but this results in an alteration in the enzyme’s shape and can no longer catalyze the reaction properly

o   Overwhelms the rate of reaction – slows down the rate of reaction more

Non Competitive Inhibition

a site on the enzyme other than the active site

Allosteric Site

super charges reaction rate by binding to an allosteric site

Allosteric Activators

non protein helper molecules

·      Many enzymes can only work if they are bound to these molecules as it promotes optimal conformation and function

·      Common dietary coenzyme – dietary vitamins

cofactors/coenzymes

reaction product is used to regulate its own further production

·      This is used to regulate enzyme activity in metabolism by using the products of enzymatic reactions to stop further enzyme activity

Feedback Inhibition

the energy that drives all bodily functions

ATP (Adenosine TriPhosphate)

decreases blood glucose by storing glucose

insulin

increases blood glucose by releasing glucose

glucagon

where are excess fats stored?

half in the adipocytes in the subcutaneous tissue under the skin, the other half in the adipocytes in other tissues and organs

acts as a energy shuttle for our bodies to enable our cells to work properly

ATP-ADP cycle

lik a compressed spring as it is stored with energy

ATP

energy released, a spring released

ADP

breaks polysaccharides into individual monosaccharides

Sugar Catabolism

·      Important in energy transfer

·      Some of the energy released is captured when ATP is formed

·      ADP is phosphorylated with energy to form ATP

Oxidation Reduction Reactions

addition of a phosphate group

Phosphorylation

3 Main Phases in Cellular Respiration

·      Glycolysis: the breakdown of glucose

·      Kreb’s Cycle

·      ETC: where we get a lot of energy

glucose into pyruvate

Glycolysis

glycogen into glucose

Glycogenolysis

when the cell is low on ATP it will get ATP from ADP by converting it to ATP and AMP

Up Regulation

when there is a lot of ATP in the cell, glycolysis does not need to make more

Down Regulation

where does the process of glycolysis occur?

in the cytosol

how much ATP and NAD+ are used to convert one glucose molecule into 2 pyruvate, and what is the gain of ATP and NADH in glycolysis

input: 2 ATP and 2 NAD+

output: 4 ATP and 2 NADH

what is the net gain of ATP from one glucose molecule in glycolysis

2 ATP

coenzyme central for metabolism and is found in every single living cell

NAD+