BIO140-501 Exam 2

main molecule of mem.

phospholipids

unique characteristic of phospholipids

has a hydrophilic phosphate head and hydrophobic lipid tail; creates a sphere in water that is selectively permeable

# of layers in a mem.

two layers of phospholipids

Why are there # layers in a mem.?

the amphipathic nature of the phospholipid molecule allows them to form bilayers spontaneously in aqueous environments b/c of the hydrophobic tails being attached to one another

Which molecules can move easily across the mem. w/o assistance?

hydrophobic molecules & small polar molecules (water); move across slowly

What cannot cross the mem. w/out aid?

Ions & large polar molecules

Why can't ions & large polar molecules cross the mem?

liposome has hydrophobic core

Purpose of cholesterol in mem. construction

keeps the mem. from being too fluid in high temps. & too solid in lower temps.; crucial in animal cells

The plasma mem is ___ state?

fluid

Why does the plasma mem. need to be fluid?

So substances can continue to pass through; floats w/ the water

mem. proteins

selectively permeable; will allow certain molecules to pass but exclude other molecules; resides w/in or on the cell mem.

transport proteins

allow large polar molecules & ions to cross the mem.; acts as channels/pumps

receptor proteins

has a binding site to intercept a messenger; causes change in protein; relays message to inside of cell

passive transport

spontaneous movement of a substance w/out the addition of energy

active transport

uses transport proteins & energy to move molecules against the concentration gradient

types of passive transport

simple diffusion, facilitated diffusion, osmosis, & filtration

diffusion

substance moves from a high concentration region to a low concentration region; moving down a concentration gradient

simple diffusion

substances that are small, uncharged, & hydrophobic can cross the mem. easily

osmosis

a form of simple diffusion; where water can move in/out of the cell

facilitated diffusion

uses transport proteins to move molecules down a concentration gradient; aid

types of active transport

sodium potassium pump, exo/endocytosis, proton pumps

concentration gradient

the difference in concentration of solutes/molecules across a mem./distance

hypertonic

a solution w/ a greater solute concentration than another

ex: tap water to distilled water

Hyper; hypo

hypotonic

a solution w/ a lesser solute concentration than another

ex: tap water to salt water

Hypo; hyper

Isotonic

solution of equal solute concentration; water moves from a hypotonic solution to a hypertonic solution

normal state for animal cells

isotonic state

normal state for plant cells

hypotonic state

Exocytosis

the process of materials that are transported to the outside of the cell via vesicles; "vomiting,” lips are plasma mem., mouth is vesicle, vomit is material

Endocytosis

the process of materials that transported inside of a cell via vesicles; "eating," lips is in plasma mem, mouth is the vesicle

Prokaryote

simple, single celled organism, lacks a nucleus & membrane bound organelles

Eukaryote

complex, contains membrane bound nucleus & organelles

Differences of Prokaryotic cell

lack a cell nucleus & organelles, has a nucleoid region, maybe flagella, 1-10 um

Differences of Eukaryotic cell

10-100 um, double-mem.-enclosed nucleus (contains DNA), have organelles

Similarities of prokaryote & eukaryote

unicellular, ribosomes, plasma mem., cytoplasm, cell wall, have genetic material

The first 3 characteristics to life

• composed of one or more cells

• reproduce autonomously using DNA

• obtain energy from the environment to support metabolism

The second 3 characteristics to life

• sense the environment & respond to it

• maintain a constant internal environment

• can evolve as groups

domain bacteria is a ___?

prokaryote

archaea is a ___?

prokaryote

domain eukarya is a ___?

eukaryote

animals, plants, fungi, & protists are ___?

eukaryote

Endosymbiotic Theory

an evolutionary theory; states that eukaryotic cells evolved by having a larger prokaryotic cell engulfing smaller prokaryotes that were not digested and eventually developed into mitochondria, chloroplasts, and possibly other organelles

evidence of Endosymbiotic Theory

mitochondria & chloroplasts contained DNA & ribosomes which were not found in other organelles outside the nucleus; were also surrounded by a double mem.

organelles apart of the Endosymbiotic Theory

mitochondria & chloroplast

nucleus

an organelle; control center; contains all of the cell's DNA, occupies 10% of inside cell space

Smooth ER

where lipids & hormones are manufactured

Ribosomes

the site of protein synthesis(translation) in the cytoplasm

Rough ER

where proteins are assembled; embedded w/ ribosomes

Golgi Apparatus

a collection of flatten mem. that packages/directs proteins & lipids produced by the ER to their final destinations either in/out side the cell

Lysosomes

an organelle; garbage/recycling center for molecules that no longer needed

Central Vacuole

lysosome version for plant cells; also stores water & aids in cells rigidity

Mitochondria

an organelle; power plant that fuels cellular activity; main source of energy for eukaryotic cells

Chloroplasts

a plant/protist organelle that captures energy from sunlight & turns it into food; photosynthesis

Cytoskeleton

a network of protein cylinders & filaments that forms the framework of a cell

Cell wall

a rigid structure made up of carbohydrates that surrounds the plasma mem. of plant, fungi, & prokaryotic cells

Plasma membrane

a barrier consisting of a phospholipid bilayer that separates a cell from its external environment with proteins interspersed; regulates what can enter/leave the cell

organelles in plant cells

cell wall, chloroplasts, plastids, small & central vacuole

organelles in animal cells

nucleus, mitochondria, endoplasmic reticulum, golgi apparatus, lysosomes, ribosomes

three components of a plant cell that lacks in an animal cell

cell wall, chloroplasts, & central vacuole

metabolism

all chemical reactions that occur inside living cells including those that release & store energy

Photosynthesis

organisms capture energy from the sun & use it to create sugars from CO2 & water; transforms light energy into chemical energy stored in covalent bonds of sugar molecules

cellular respiration

sugars are broken down into energy, usable by the cell

chemical equation for photosynthesis

CO₂ + H₂O + light → C₆H₂O + O₂ + H₂O

chemical equation for cellular respiration

C₂H₁₂O₆ + O₂ → CO₂ + H₂O + energy

main purpose of photosynthesis

converts light energy into stored chemical energy that photosynthetic organisms use to grow, develop, & cellular functions

main purpose of cellular respiration

break down glucose to produce ATP; the usable energy for cellular function

similarities of photosynthesis & cellular respiration

metabolic processes that drive conversion in living organisms; utilize ETC; create proton gradients; produce ATP

differences of photosynthesis from cellular respiration

anabolic reaction, occurs in chloroplasts (plants/algae), reactants & products are opposite

Differences of cellular respiration from photosynthesis

catabolic reaction, occurs in mitochondria of all eukaryotes, reactants & products are opposite

organisms capable of photosynthesis

only photosynthetic organisms; plants, bacteria, algae

organisms capable of cellular respiration

occurs in all organisms; animals & plants

What does photosyn. consume?

carbon dioxide & ATP

What does cell res. consume?

Oxygen & glucose

What does photosyn. produce?

oxygen, glucose, & ATP

What does cell res. produce?

Carbon dioxide & ATP

Organelle responsible for photosyn.?

chloroplast

Organelle responsible for cell res.?

mitochondria

Photo syn. Electron storage in what form?

NADPH

Cell res. Electron storage in what form?

NADH & FADH2

light dependent reactions

chlorophyll molecules absorbs & converts light energy into chemical energy: ATP & energized electrons of NADPH; the process includes the splitting of water, which produces O2 into the atmosphere; first stage of photosyn.

light independent reactions

Series of enzyme-catalyzed chemical reactions convert CO2 into sugar, powered by ATP, energized electrons of NADPH, & H ions donated by NADPH; second stage of photosyn.

What is needed for LDR?

light energy & H₂O

What is needed for LIR?

ATP, NADPH, & CO₂

What is produced at the end of LDR?

ATP, NADPH, & O2

What is produced at the end of LIR?

glucose

Another name for light independent reactions

Calvin cycle or carbon fixation

Chlorophyll

green pigment; specialized in absorbing light energy

importance of chlorophyll

crucial role in photosyn. by absorbing light energy

Plant tissue structure

plant cell > chloroplast > thylakoid mem. > chlorophyll

the three stages of cellular respiration

glycolysis, Krebs cycle, & oxidative phosphorylation

glycolysis

sugars are split to make the three-carbon compound pyruvate; for each glucose molecule split, two molecules of ATP & two molecules of NADH are released

Krebs cycle/citric acid cycle

sequence of enzyme driven reactions, pyruvate is broken down, releases CO₂ & produces energy carriers: ATP, NADH, & FADH₂

oxidative phosphorylation

electron transport chain uses energized electrons from NADH & FADH, to pump H+ across the mem. to create a gradient, H+ flow through the ATP synthase, generates lots of ATP; electrons & H atoms are removed from NADH & FADH₂, and given to O₂ to make H2O

NADH & FADH₂ store?

electrons

ATP store?

energy

ATP

small organic molecule that stores energy & carries it from one part of a cell to another; Adenosine TriPhosphate

role of ATP

powers almost all cellular activity

Location of glycolysis

cell cytoplasm

Location of Krebs cycle

mitochondria matrix