Biology - Cell Transport and Chemical Reactions

Functions of the cell membrane

Separates a cell from its environment, provides protection and support, controls input and output.

Homeostasis

Internal equilibrium

What is the cell membrane made of?

A double phospholipid bilayer

The phosphate head is _____ and ______. It is exposed to _____.

polar, hydrophilic, water

The _____ acid tails are _____ and ______. They are shielded from _______.

fatty, non-polar, hydrophobic, water

Why does the cell membrane have pores in it?

Allows the membrane to be selective

Is the membrane fluid or solid?

Fluid

Name 2 ways the plasma membrane's fluidity is maintained:

Kinked fatty acid tails keep the membrane from packing together, and cholesterol adjusts the fluidity depending on the temperature.

Glycoprotein

A protein with attached sugars

Glycolipid

A lipid with attached sugars

Are all carbohydrate chains the same?

No, they vary from cell to cell.

Purpose of carbohydrates in the plasma membrane:

Identification tags that are recognized by other cells, allows embryos to form into tissues and organs, enables the immune system to reject bacteria.

The 2 membrane proteins are:

Structural and Globular proteins

Structural proteins provide _____ for the cell and is linked to the ______.

support, cytoskeleton

Globular proteins act as ______ for catalytic reactions and are _____ for chemical messages.

enzymes, receptors.

What molecules are the plasma membrane permeable to?

Small non-polar molecules such as oxygen and carbon dioxide.

What molecules are the plasma membrane impermeable to?

Ions, glucose, water.

Transport proteins location

Found all throughout the membrane

2 other names for transport proteins

Integral, Transmembrane

Peripheral proteins

Proteins loosely attached to the surface of the membrane

Passive transport is when the cell _________.

doesn't use energy

3 kinds of passive transport:

Diffusion, Facilitated Diffusion, Osmosis

Active Transport is when the cell _______.

does use energy

3 kinds of Active Transport:

Protein Pumps, Endocytosis, Exocytosis

Passive transport: high to low, or low to high?

high to low

Diffusion is the _____ movement of molecules from a _____ to _____ concentration

random, high, low

Facilitated diffusion is a kind of diffusion in which ______ particles diffuse through ________ ______ found in the plasma membrane.

specific, transport proteins

Channel proteins are shaped like:

A hollow channel

True or False: Carrier proteins change their shape while transporting a molecule

True

Osmosis is the diffusion of _______ through a ________ membrane.

water, plasma

solute

the dissolved particles in a solution

solvent

a liquid substance that dissolves the solute

solution

the result of the solvent dissolving the solute

True or False: In Osmosis, both the solute and water can pass through the membrane.

False. Only water can pass through

What energy does Active Transport need?

ATP

ATP is made by which cell organelle?

Mitochondria

Protein pumps are _____ proteins that move molecules

carrier

This protein pump takes in 3 NA+ and releases 2 K+

Sodium-Potassium Pump

Endocytosis is the act of taking _____ into a ____.

particles, cell

3 kinds of Endocytosis:

Phagocytosis, Pinocytosis, Receptor-mediated Endocytosis

Phagocytosis is "cell _____" and occurs when the membrane forms a ______ to let the "____" in.

eating, vacuole, food

Pinocytosis is "cell _____" and occurs when the membrane forms a _____ to let the extracellular ____ in.

drinking, vacuole, fluid

Receptor-mediated endocytosis is a form of taking in molecules with a _____ receptor on the _____.

protein, surface

Exocytosis is when the cell releases _____ out of the cell. Examples include ____ or waste.

material, hormones

tonicity

the capability of a solution to modifiy the amount of water in a cell

3 kinds of solutions include:

Hypotonic Solution, Hypertonic Solution, Isotonic Solution

A Hypotonic Solution is when the _____ has a lower concentration of solutes and a _____ concentration of water than the _____.

solution, higher, cell

As a result of the hypotonic solution, water moves _____ the cell.

into

In a Hypotonic Solution, plants become ____ and animal cells _____. This is called ______.

turgid, burst, cytolysis

A Hypertonic Solution is when the ____ has a lower concentration of solutes and a _____ concentration of water than the _____.

cell, higher, solution

As a result of the hypertonic solution, water moves _____ the cell

out of

In a Hypertonic Solution, plants ____ (____) and animal cells _____.

shrivel, plasmolysis, shrivel

An Isotonic Solution is when the ____ and the _____'s concentrations of solutes water are _____.

cell, solution, equal

As a result of an isotonic solution, water moves ______ of the cell.

in and out

In an Isotonic Solution, plants become _____ and animals are _____.

flaccid, normal

Turgor pressure

The force that pushes the plasma membrane against the cell wall

How do kidneys keep the blood isotonic?

Removes excess salt and water

Metabolism is

all of the chemical reactions that occur in the body

A Metabolic Pathway is when a ____ goes through a series of _____ changes by _____. These changes include ____ down and ______ smaller molecules,

molecule, chemical, enzymes, breaking, assembling

Catabolic Pathways

When a molecule is broken down. It releases energy

An example of a catabolic pathway is _______.

cellular respiration

Anabolic Pathway

when the molecules are assembled. this requires energy

An example of an anabolic path way is ________.

photosynthesis

Kinetic is energy of _____.

motion

2 kinds of kinetic energy:

heat and light

Potential energy is energy ______.

that matter possesses

Chemical energy is the potential energy of ______.

molecules in a chemical reaction

Thermodynamics

the study of energy transformations

system (thermodynamics)

the matter under study

surroundings (thermodynamics)

everything outside of the system

First Law of Thermodynamics: energy cannot be ______. it can only be _______

created or destroyed, converted

Second Law of Thermodynamics: energy transformations cause _______, and some energy is lost as _____.

disorder, heat

entropy

degree of disorder

a cell is an island of low __________ in an ____________ universe

entropy, random

Endergonic reactions _____ energy

absorb

Are endergonic reactions random?

No

Exergonic reactions ________ energy

release

Are exergonic reactions random?

Yes

Energy coupling is when:

an exergonic process starts an endergonic process

ATP is made of:

ribose sugar, adenine (nitrogenous base), chain of three phosphate groups

Where is ATP's energy stored?

the bonds between the phosphate groups

Hydrolysis of ATP results in:

ADP

What happens in ATP hydrolysis?

The third phosphate group breaks away, releasing energy

What chemical reaction is ATP hydrolysis coupled with?

Phosphorylation

What happens in phosphorylation?

Energy is absorbed from ATP hydrolysis to attach the third phosphate group to another molecule.

3 roles of ATP include:

starting endergonic reactions, movement of the cell, active transport

A working cell may consume _____ ATPs/sec

10 million

What are the two main roles of enzymes?

Acting as catalysts and controlling chemical reactions in the cell.

What does ATP stand for?

Adenosine triphosphate

What is a catalyst?

substance that speeds up a chemical reaction by lowering activation energy barrier

Enzymes are _________

biological catalysts

What is a substrate?

The chemical an enzyme alters

What is an active site?

The pocket or groove where the substrate fits

Do enzymes accept all molecules?

No.

What is the induced fit hypothesis?

The idea that an active site adjusts its shape when it binds to a substrate

Human enzymes work best in temperatures around (_______)

95-104 Fahrenheit

The optimal pH value for most enzymes are around _______

pH 6-8

Holoenzyme

An enzyme that functions with the help of another molecule

apoenzyme

the enzyme part of the holoenzyme

cofactors

inorganic helpers in the holoenzyme