Biology 1130 final

Homeostasis

A tendency to maintain a balanced or constant internal state; the regulation of any aspect of body chemistry, such as blood glucose, around a particular level

cell signaling helps to maintain homeostasis
T or F

True

Explain: Signal transmission

Signal transmission is the synthesis, release, and transport of signaling molecules such as hormones, local regulators, and neurotransmitters. These signaling molecules will induce some type of response in another target cell.

Explain: signal reception

Reception is the target cell's detection of a signaling molecule coming from outside the cell. A chemical signal is "detected" when the signaling molecule binds to a receptor on another cell.

Explain: signal transduction

Signal transduction is a step or series of steps that converts the signal to a form that can bring about a specific cellular response. This is often a multi-step process involved many different molecules.

Explain: signal response

the transduced signal finally triggers a specific cellular response. These responses can include the opening/closing of channels in the plasma membrane, a change in a metabolic process, or the activation/repression of a gene.

which step does signal transduction pathway occur?

signal transduction

List the four main processes of cell signaling, in order

1. transmission
2. reception
3. transduction
4. response

4. response

local regulators

A local regulator is a signaling molecule that diffuses through the interstitial fluid, the fluid surrounding the cells, and acts on nearby cells. They are involved in local signaling (paracrine signaling)

Name the 3 types of signaling molecules

local regulators, neurotransmitters, hormones

neurotransmitters

also involved in local signaling (synaptic signaling). These signaling molecules are only produced by neurons (nerve cells)

Hormones

chemical messengers produced in one region of the body and transported to another region where they produce a cellular response. These molecules are typically involved in long distance signaling where they are transported to other parts of the body via the circulatory system

What is the lock and key model?

This model proposes that enzymes work in the same way as a key operates only a single lock. A substrate will only fit the active site of one particular enzyme.

What are ligands?

A specific molecule that binds to a specific target receptor

what are the three main cell surface receptors?

Ion channel-linked, G protein-linked, enzyme-linked

Ion channel-linked receptors

also called ligand-gated channels, which means that the ion channel opens or closes in response to the binding of the signaling molecule. They convert chemical signals to electrical signals

G-protein-linked receptor

G protein-linked receptors couple certain signaling molecules to various signal transduction pathways inside the cell.

Enzyme-linked receptors

transmembrane proteins with a binding site for a signaling molecule outside the cell and an enzyme component inside the cell. They bind certain hormones that regulate many cellular processes (insulin & growth factors) and are important in development

Imagine you have developed a pharmaceutical drug called Drug X. Drug X blocks phosphorylation of kinase proteins in a cellular signal transduction pathway.

How would this drug impact the signaling cascade within the cell and the cellular response?

In this signal transduction pathway, the signal is relayed from one molecule to the next through phosphorylation of the different protein kinase molecules. If phosphorylation is inhibited, the signal cannot be relayed and response will not be produced in the cell.

what are three possible cell signal responses?

specific genes are suppressed or activated, enzyme activity changes, ion channels open or close

signal amplification

turns one signal molecule into multiple second messenger molecules

signal termination

The process that stops signal transduction.

Metabolism

All of the chemical reactions that occur within an organism

Define anabolism

the synthesis of complex molecules in living organisms from simpler ones together with the storage of energy; constructive metabolism. (cytoplasmic membrane, cell wall, etc.)

Define catabolism

the breakdown of complex molecules in living organisms to form simpler ones, together with the release of energy; destructive metabolism. (amino acids, nucleotides, etc)

Define energy

the capacity to do work

Which energy form is not interconvertible and does not have energy?

heat energy

Potential vs. Kinetic Energy

Potential: stored energy

Kinetic: energy of motion

1st law of thermodynamics

Energy cannot be created or destroyed

2nd law of thermodynamics

Energy cannot be changed from one form to another without a loss of usable energy

exergonic reaction

There is a net loss of free energy, products have less free energy than was present in the reactants, and the reaction proceeds spontaneously

endergonic reaction

A non-spontaneous chemical reaction in which free energy is absorbed from the surroundings. net gain of free energy

Why is ATP important?

TP is the energy currency of the cell (temporarily stores energy in chemical bonds)

How is ATP created?

bonding a 3rd phosphate group to an ADP molecule

How is ATP broken down to ADP

when ATP loses a phosphate group, it releases energy and is now an ADP molecule

explain Redox reaction:

Chemical reaction in which the oxidizing agent is reduced and the reducing agent is oxidized

What does it mean for something to be oxidized?

lose electrons (loss of H+ atoms usually means loss of e-)

What does it mean to be reduced?

gain of electrons

Acronym for redox rxns

LEO: Lose Electrons= Oxidation
GER: Gain Electrons= Reduction

Enzymes

Catalysts for chemical reactions in living things
(Enzymes increase the speed of a reaction (lower activation energy) without being consumed. Enzymes do not alter concentrations of reactants or products)

Give the chemical equation for aerobic respiration

C6H12O6 + 6O2 >>> 6CO2 + 6H2O + energy

Net yield of ATP at the end of aerobic resp.?

36-38

What is the importance of energy-carrying molecules such as NADH and FADH2 in aerobic respiration?

NADH and FADH2 deliver high energy electrons to one electron acceptor in the chain, NADH creates 28-30 ATP

Compare and contrast aerobic respiration, anaerobic respiration, and fermentation

All 3 are similar in that these processes are all ways for a cell to go through cellular respiration. Aerobic resp. requires oxygen to go through all of cellular respiration, while fermentation and anaerobic resp. do not. Anaerobic resp. uses inorganic molecules to replace oxygen as the final E- acceptor and Co2 and H2O are broken down. Fermentation is also an anaerobic process by which glucose is broken down; the ATP and organic compounds created from that action serve as the final E- donor and acceptor instead of oxygen.

stages of aerobic respiration

1. Glycolysis
2. Formation of Acetyl CoA
3. Krebs Cycle
4. Electron Transport Chain/ Chemiosmosis

Glycolysis
- location in cell
- starting molecule
- molecules produced

location: cytosol (only one not in mitochondria
starting molecule: glucose, 2 ATP
molecules produced 2 ATP, 2 NADH, 2 Pyruvate

Summary of Glycolysis

There are 2 phases to glycolysis:- 1. Energy invest: endergonic rxn, start with 2 ATP and glucose and yields 2 G3P + 2 ADP molecules- 2. Exergonic, G3P is converted to pyruvate, 2 NADH and 4 ATP are formed - Yield: 2 ATP, 2 NADH, 2 Pyruvate

Formation of Acetyl CoA
-location
-starting molecule
-molecules produced

location: mitochondria
starting molecule: 2 molecules of coenzyme A
molecules produced: 2 ATP, 2 NADH, 2 Acetyl CoA, 2 CO2

Summary of Acetyl CoA formation

We are now in the mitochondria of the cell, each pyruvate loses 1 CO2, the removed carboxyl group leaves as CO2. What is left is the acetyl group which now binds to coenzyme A = Acetyl CoA

citric acid cycle
location
starting molec.
products

location: inner mitochondria matrix
CoA enzyme
6 NADH, 2 FADH, 2 ATP, 4 CO, 2 Oxaloacetate

What is alcoholic fermentation?

Anaerobic sugar breakdown pathway that produces ATP, CO2, and ethanol.

lactate fermentation

anaerobic sugar breakdown pathway that produces ATP and lactate

What is photosynthesis?

the process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

Where does photosynthesis occur?

chloroplasts of mesophyll cells

What is the role of the stomata in photosynthesis?

They open to allow carbon dioxide in, and let oxygen out. They also allow water to evaporate out of the plant when open.

What are the steps of photosynthesis?

light reactions and calvin cycle

overview of light dependent reactions

WHAT→ photosynthetic reactions that requires light.
that requires light.
WHERE → thylakoid (membrane & inside)
HOW → uses light & water to produce oxygen and converts ADP to ATP and NADP+ to NADPH
"WHO" → Photosystem II & Photosystem I
Various proteins embedded in the thylakoid membrane
WHY → captures sunlight energy to produce ATP which will eventually be used to construct the glucose molecules.
WHEN → when the sunlight shines

noncyclic electron transport

In photosynthesis, the flow of electrons forms ATP, NADPH, and O2. (photosystem 1 and PS 2)

cyclic electron transport

In photosynthetic light reactions, the flow of electrons that produces ATP but no NADPH or O2. (Photosystem 1 (P700) only!)

Calvin Cycle

light-independent reactions of photosynthesis in which energy from ATP and NADPH is used to build high-energy compounds such as sugar

starting molecules of carbon fixation

Ribulose bisphosphate. CO2, ATP, NADPH, necessary enzymes

carbon fixation end products

carbs, ADP + P, NADP

Photorespiration

A metabolic pathway that consumes oxygen and ATP, releases carbon dioxide, and decreases photosynthetic output. Photorespiration generally occurs on hot, dry, bright days, when stomata close and the O2/CO2 ratio in the leaf increases, favoring the binding of O2 rather than CO2 by rubisco.

C4 vs CAM plants

Same Except For:
-C4 plants separate 2 steps of C fixation anatomically in 2 different cells (Mesophyll and Bundle Sheath)

-CAM plants separate 2 steps of C fixation temporally at 2 different times (Just Mesophyll)

list the 7 types of connective tissue

loose and dense
elastic
adipose
cartilage
bone
blood

loose connective tissues

collagen and elastic fibers
covering for nerves, muscles, blood cells and blood vessels
forms the subcutaneous layer, skin to muscle (filling between body parts)

dense connective tissue

collagen fibers
tendons, ligaments, dermis skin layer
forms tendons and ligaments; support system

elastic connective tissue

elastic fibers (parallel)
located in structures that expand and contract
allow for elasticity and movement

reticular connective tissue

reticular fibers, located in the spleen or liver, forms the support framework for for organs

adipose connective tissue

mainly fat cells
subcutaneous layer and cushioning tissues
stores fat and releases it when fuel is needed

cartilage connective tissue

non-vascular chondrocytes (bone cells)
in bone and spongier parts (ear, nose, etc.)
supports vertebrate skeletons in early development

bone connective tissue

red and white blood cells and platelets (all in plasma)
vascular systems, red marrow becomes blood
cells communicate in intracellular substances, messages to other parts of the body

skeletal muscle tissue
- location
- type of control
- striations?
- speed of contraction

- large muscle masses attached to bones
- voluntary control
- striated
- rapid speed of contraction

smooth muscle tissue

- walls of the digestive tract, uterus, etc.
- involuntary control
- not striated
- slowest contraction

Explain negative feedback

conditions in the body change from set point
a change is detected
corrective mechanism is activated
return to set point
corrective mechanism is shut off
conditions in the body change from set point

tends to slow down a response
most common type of feedback

Explain positive feedback

effects of a small disturbance on a system include an increase in the magnitude of the perturbation. That is, A produces more of B which in turn produces more of A.

What makes up vertebrate skin?

Epidermis (stratum corneum and stratum basal) dermis, and subcutaneous tissue

hydrostatic skeleton

A fluid skeleton in many soft-bodied invertebrates, including annelids, that allows an organism to change shape but not volume.

exoskeleton

A body covering, typically made of chitin, that provides support and protection (beetles "crunch" sound comes from this)

endoskeleton

internal skeleton or supporting framework in an animal/human

axial skeleton

The portion of the skeleton that supports and protects the head, neck, and trunk

appendicular skeleton

bones of the shoulder, pelvis, and upper and lower extremities

agonist vs antagonist muscle

In an antagonistic muscle pair as one muscle contracts the other muscle relaxes or lengthens. The muscle that is contracting is called the agonist and the muscle that is relaxing or lengthening is called the antagonist.

muscles work _______ against eachother.

antagonistically

list in order of largest to smallest
- muscle fiber
- sarcomeres
-myofibrils (myosin and actin)
-muscle

1. muscle
2. muscle fibers
3. myofibrils
4. sarcomeres

smallest muscle unit

sarcomeres

List the steps of muscle contraction

1. motor neuron releases Acetylcholine into synaptic cleft, Na+ ion channels are opened up, action potential is generated in sarcolemma by Na+ channels opening up
2. The action potential travels across the plasma membrane, down T-tubules (depolarizes them), calcium ion channels are opened, Ca2+ molecules escape into myofibrils
3. When Ca2+ molecules bind to troponin it changes the shape, tropomyosin filaments are pushed away from the active sites on the actin, binding sites are now exposed
4. (On the myosin filament, the thick band above actin with the myosin head) there is an ATP binding site. ATP molecule binds to the ATP binding site on myosin and splits into ADP + Pi, the myosin head binds to actin forming a cross-bridge
5. Pi is released from the myosin head and triggers the "power stroke", it is not cocked at 45 degrees
6. the myosin head pulls the binded actin forward towards the center of the sarcomere, ADP releases as the muscle shortens
7. the myosin head binds to a new ATP molecule and detaches from the actin filament, actin-myosin complex binds to ATP
(at this point the cycle may return to step 3 if enough Ca2+ ions are available)

List the 5 parts of the neuron

dendrites
cell body
axon
Schwann cells (myelin sheath)
nodes of ranvier

resting potential of a neuron

neuron at rest (~-70mV)

factors that affect resting potential

2 factors determine resting potential:1. Concentration of Na+ & K+ inside/outside cell2. Selective permeability of plasma membrane to Na+ & K+

role of dendrites

receive and transmit signals to the cell body

role of the axon

a single axon transmits a signal from its cell body to anther cell or tissue

What is a glial cell?

cells in the nervous system that support, nourish, and protect neurons

Schwann cells and myelin sheath

Surrounds some neurons to increase how efficiently it can carry an impulse

Nodes of Ranvier

a gap in the myelin sheath of a nerve, between adjacent Schwann cells.

How is action potential generated?

If a stimulus exceeds a certain threshold value a change in potential of the membrane is achieved by the membrane becoming more permeable to sodium ions by the opening of sodium voltage-gated channels causing a RAPID/SUDDEN influx of sodium and the depolarization of the membrane.

How does depolarization occur?

The stimulus opens up gated ion channels causing Na+ inflow into the neruon