AP Biology Unit 2

What are emergent properties?

bringing together simple units to make a more complex unit

What are the three parts of cell theory?

All organisms are made up of cells

The cell is the fundamental unit of life

Cells came from preexisting cells

What is life? (biologically...)

ability to reproduce, respond to the environment, harness energy from the environment and evolve over time

What are the three universal properties of cells?

maintaining homeostasis, store and transmit information, and transfer energy

What are the functions of the cell membrane?

acquiring and exchanging ions and the building blocks of macromolecules

releases waste products into the environment

What is homeostasis?

the active maintenance of stable internal conditions of a cell

Why is homeostasis necessary in cells?

it is important for maintain chemical reactions, protein folding, and other cellular functions

Why is homeostasis an "active process"?

it requires continual interplay between the inside and outside of the cell

What are proteins?

key structural and functional molecules that do the work of the cell

How do cells reproduce?

DNA guides the synthesis of RNA which is then used to direct protein synthesis (Central Dogma)

Why are cells dependent on proteins?

they determine internal structure, shape, ability to move, and various chemical reactions

What are ribosomes?

complex structure that is a site where the protein is assembled (translation)

What is metabolism?

chemical reaction by which cells transfer energy from one form to another and build and break down molecules

What is ATP?

stored energy made from chemical reactions that enable growth, division, and moving substances into and out of the cell

What is catabolism?

set of chemical reactions that break down molecules into smaller units (release ATP/heat)

What is anabolism?

set of chemical reactions that build molecules from smaller units and require an input of energy (ATP)

(synthesizes carbohydrates and proteins)

How does protein structure determine its function?

the order of amino acids (R-groups) determine the folding

How does DNA structure aid in its function?

the double helix can divide due to weak hydrogen bonds and can then be replicated

What is the nucelus?

house of genetic information

What is cytoplasm?

space between organelles in a cell

What are prokaryotes?

cells without a nucleus and membrane-bound organelles

What are the two domains of prokaryotes?

Bacteria and Archaea

What are the properties of prokaryotes?

no nucleus

have flagella

plasmids

asexual

DNA in nucleoid

cell wall = peptidoglycan

more chemically complex

How is DNA organized in prokaryotes?

located in the nucleoid in strands in many loops

OR

in plasmids (circular molecules of DNA)

How are the domains of prokaryotes different?

structure of the cell wall, how DNA synthesizes RNA and relationships to eukaryotes

What are eukaryotes?

cells with a nucleus

What is a eukarya?

domain consisting of all organisms that have a nucleus; includes protists, plants, fungi, and animals

How does DNA travel to replicate?

directs synthesis in the nucleus then RNA synthesizes protein in the cytoplasm

How is DNA replication different in prokaryotes and eukaryotes?

Prokaryotes: Single process

Eukaryotes: Multiple regulated processes

What are organelles?

membranes that divide the cell contents into smaller spaces specialized for different functions

What are the key properties of eukaryotes?

nucleus

many linear chromosome

complex regulation of DNA and RNA

Ribosomes

Cilia

What is the cytosol?

jelly-like material outside of the nucleus and organelles

What are the major differences between the eukaryotes and prokaryotes?

RNA/protein synthesis, ribosome size, lipids that make up membranes, and flagella vs. cilia

What are cilia?

rodlike structures that extend from the surface of the cell

What are nonmotile cilia?

cilia that don't move and serve as a sensory function

What are motile cilia?

cilia that move and propel the movement of cells or fluid

What is surface area?

the total amount of area of the outer surface of an object

What is the cytoskeleton?

protein fibers to maintain shape and assist in movement

Why is the surface area to volume ratio important?

-If the ratio is too small then substances will not enter the cell as quickly

- If the ratio is too small then cells may overheat because the metabolism produces heat faster than it is lost

What are vesicles?

small membrane-enclosed sacs that transport substances within a cell or from the interior to the exterior of the cell

What is the function of vesicles?

take pieces of membrane or internal contents of the organelle then fuse with the membrane to re-fuse or unload their contents

What is the endomembrane system?

the interconnected membranes of the cell (chemical communication system)

What is the function of the endomembrane system?

Allows for the cell to compartmentalize different areas to serve different functions (diversity of enzymes)

What is the endoplasmic reticulum?

an organelle involved in the production of proteins and lipids

single membrane

Why does the ER need increased surface area? (maze-structure)

to allow for larger protein production via ribosomes

What is the difference between free ribosomes and membrane bound ribosomes?

Free ribosomes send proteins directly to the cytoplasm (not other organelles or membrane)

What are enzymes and where are they made?

proteins (rough ER) that accelerate the rate of a chemical reaction

What is the function of the smooth ER?

site of fatty acid and phospholipid synthesis

Why do cells have organelles?

increase surface area

cell specialization (aid in function)

protection

resource managers (chemical concentration variations)

What is the nuclear envelope?

double membrane that surrounds the nucleus

What are nuclear pores?

holes in the nuclear envelope where things can pass into and out of the nucleus

What is the function of the golgi apparatus?

sorts and modifies proteins and lipids from the ER

acts as a sorting satiation

where carbohydrates are added to proteins/lipids

single membrane

What are cisternae?

flattened membranous sacs in the golgi apparatus

How do molecules move through the endomembrane system?

vesicles

Why do proteins move backward from the golgi?

if there was an error in production or to recycle components

What are lysosomes?

specialized vesicles derived from the golgi that degrade damaged or unneeded macromolecules

What is the mitochondria?

organelles that harness energy from organic molecules (mostly carbohydrates)

What is chemical respiration?

a series of chemical reactions in which organic molecules are broken down and the energy stored in organic molecules is converted to ATP

Describe the membrane structure of a mitochondria.

an outer membrane and a highly convoluted inner membrane whose folds project into the interior

What is the mitochondrial matrix?

space enclosed by the inner membrane

Where does cellular respiration occur?

cytosol, mitochondrial matrix and inner mitochondrial membrane

What is the chloroplast?

organelle that captures energy of sunlight to synthesize simple sugars (plants/algae only)

double membrane

What is photosynthesis?

process of capturing sunlight to synthesize simple sugars (Co2 in, O2 out)

What is a thylakoid?

The organelle in which light dependent reactions take place.

What is a grana?

the stacks of thylakoids embedded in the stroma of a chloroplast.

What is chlorophyll?

light collecting molecule (pigment)

serves key role in ability to capture energy

What are microfilaments?

extensively branch beneath the cell membrane and reinforce the cell membrane and organize proteins a associated with it

What are microtubes?

hollow tubelike structures that help maintain cell shape and internal structure

What are the functions of microtubes?

help the cell withstand compression and guide the arrangement of organelles in the cell

What is the function of the cell wall?

provide structural support and protection of the cell because it is rigid and resists expansion

What is the cell wall composed of?

carbohydrates, proteins, polysaccharide, cellulose***

What is turgor pressure?

the force exerted by water pressing against an object

(provides structural support in plants)

What is the function of the vacuole?

absorb water and contribute to turgor pressure

store water, nutrients, ions, and waste

Why do cells expand?

water pressure and chemical concentration variation

What is volume?

total amount of space an object occupies

Why do some cells want a larger surface area?

more movement of stuff into and out of the cell

Which increases faster: volume or surface area? Why is this helpful?

Volume, used to determine growth of organisms

What is isometry?

same measure/shape but an increase/decrease of size

What is allometry?

different measure/shape with a change of size

What is diffusion?

net movement of molecules from regions with higher concentrations to regions of low concentration

What are the pros and cons of diffusion?

Cons: takes a long time

Pros: disposes waste and energy

What is bulk flow?

the movement of a fluid driven by pressure differences

(used to transport nutrients to places far away from source)

What is the function of the cell membrane?

separates cells from their external environment and defines compartments within eukaryotic cells that allow them to carry diverse functions

What does amphipathic mean?

having both hydrophilic and hydrophobic regions

Describe the structure of phospholipids.

phosphate head (polar, hydrophilic)

fatty acid tails (nonpolar, hydrophobic)

What makes up a micelle membrane?

lipids with bulky heads + single fatty acid tail

What makes up a rectangular membrane?

lipids with smaller heads and double fatty acid tails

What is the lipid bilayer?

two layers of lipids in which the hydrophilic head group are on the outside (intact with water) and the hydrophobic tails are sandwiched inbetween

What are liposomes?

spherical structures with an inner and outer space (resembles a cell)

What does "dynamic membrane" mean?

fluid with lateral movement of lipids and other components to allow for versatility

Why is the cell membrane "dynamic"?

weak van der Waals forces break and travel quickly with flexibility

How do we determine membrane fluidity?

Long fatty acid chains = less fluid

# if carbon-carbon bonds in tails (saturated is less fluid)

How does cholesterol impact membrane fluidity?

High temperature makes it more fluid and lower temperature makes it less fluid

What is the function of cholesterol in the cell membrane?

helps maintain a consistent state of membrane fluidity by preventing dramatic transitions in fluidity as temperature changes

What are lipid rafts?

lipids assembled in a defined patch (anchor points) in the cell membrane

What are transport proteins?

proteins which move ions or other molecules across the membrane

What are receptor proteins?

proteins that allow the cell to receive signals from the environment

What are some functions of proteins in the cell membrane?

transport

receptor

speed up chemical reactions

serve as anchors

maintain structure and shape

What are integral proteins?

proteins permanently associated with the membrane

What are transmembrane proteins?

proteins that extend for the entire membrane