Unit 2

this took forever T-T

Wha is the plasma membrane also known as?

phospholipid bilayer

What is the cytoplasm?

all the material contained inside cell membrane

What is the semifluid substance found inside the cell (intracellular fluid) known as?

cytosol

What is the double membrane of the mitochondria made of?

phospholipid bilayer

What two spaces does the two membranes of the mitochondria separate?

the intermembrane space and the mitochondrial matrix

What is aerobic cellular respiration?

sugar (or food) + oxygen —> carbon dioxide + water + ATP

What are thylakoids?

a membranous system in the shape of flattened, interconnected sacs

What is a granum?

a stack of thylakoids

What three spaces does the membranes of the chloroplast separate?

stroma (fluid space ouside the thylakloids), thylakoid space (inside the thylakoids), and intermembrane space

What is stoma?

holes on the underside of leaves

What green pigment does chloroplasts contain?

chlorophyll

What is a glycoprotein?

a molecule with sugar and protein

What is a glycolipid?

a molecule with sugar and fats

What is photosynthesis?

converts solar energy from the sun into chemical energy (such as sugar) that can be used by cells

What are the main functions of the plasma membrane?

• controls what goes in and out of the cell’

• Allows cells to communicate w/ each other

What is the lipid component of the plasma membrane called?

phospholipid bilayer

Why are smaller cells more advantageous in efficiency?

larger surface area to area ratio allows them to transport materials more

What are the types of protein molecules in the cell membrane?

peripheral or integral

What are integral proteins described as?

amphipathic, aka both hydrophobic and hydrophilic regions

What is diffusion?

the act of molecules moving from a more concentrated area to a less concentrated area

What is osmosis?

diffusion of water

How are prokaryotic cells characterized?

has no nucleus

How are eukaryotic cells characterized?

has nucleus & other membrane-bound organelles

What is the nucleoid?

the region in the prokaryotic cell where DNA is located

What is a cell wall and what is it made of (in prokaryotes)?

rigid structure outside the cell membrane, made of carbohydrate peptidoglycan

What is the flagella?

locomotion organelles of some bacteria

Eukaryotic chromosomes are (linear/nonlinear).

linear

What are the three domains of life?

bacteria/prokaryotes, archaea, eukarya

What is taxonomy?

the science of defining and naming groups of biological organisms based on shared characteristics

What organelles does a plant cell have that animal cells don’t?

large central vacuole, chloroplast

What organelles does an animal cell have that plant cells don’t?

centrioles, lysosomes

What makes up the endomembrane system in eukaryotic cells?

• Nucleus

• Endoplasmic reticulum

• Golgi apparatus

• Lysosomes

• Various types of vesicles and vacuoles

• Plasma membrane

What is the complex of DNA and proteins called?

chromatin (also known as uncoiled chromosome)

What is the nucleus enclosed by?

nuclear envelope (two lipid bilayers)

How does the nucleus allow material to enter and leave?

through nuclear pores in the nuclear envelope

What are the two regions of the ER?

rough ER, smooth ER

What is the main function of the Rough ER?

synthesize proteins through the embedded ribosomes

What are the steps of protein synthesis from ribosomes in Rough ER?

1. Embedded ribosomes build the polypeptide chain

2. Polypeptide is modified and put into transport vesicle

3. Transport vesicle travels to Golgi Apparatus, where they are modified more

4. Sent to final destination in transport vesicles

What are the two locations that ribosomes are found and what are they called?

Bound ribosomes: attached to rough ER

Free ribosomes: found suspended in the cytoplasm

Where do proteins made by free ribosomes go?

stays inside cytosol of cell

Where do proteins made by bound ribosomes go?

goes outside the cell

What is the main function of the smooth ER?

synthesize lipids

What does the smooth ER contain?

metabolic enzymes

• ex. Calcium ions, which is used for muscle contractions

What is a lysosome?

a vesicle containing hydrolytic enzymes that are used to digest (break down) macromolecules

Where are hydrolytic enzymes made?

rough ER, then modified in Golgi Apparatus

What is apoptosis?

when a cell programs itself to die, lysosomes release hydrolytic enzymes within the cell to break down structures in the cell (this process is similar to hydrolysis)

What is phagocytosis?

a process in which a cell engulfs materials from outside the cell

• ex. Food vacuoles

What do contractile vacuoles do?

pump excess water out of cells

Why do cells need hormonal systems?

functions as a second control system, which helps cells communicate

Would a cuboid cell that measures 2cm across or 4cm be more efficient at transporting things in and out of the cell?

2 cm, there is a higher surface area to volume ratio (3:1 > 3:2). This allows the cell to have more space to transport things in and out

How does water, a polar molecule, travel through the phospholipid bilayer?

aquaporins, a type of integral membrane protein

What two compartments in the mitochondrion is separated by the double cell membranes?

mitochondrial matrix and intermembrane space between the two membranes

What is aerobic cellular respiration?

when sugar and oxygen are converted into carbon dioxide, water, and ATP

What membranous system is inside the chloroplast?

thylakoids

What is a stack of thylakoids called?

granum

What is the fluid outside the thylakoids called?

stroma

What is the endosymbiotic theory?

an early prokaryotic ancestor of the eukaryotic cells was engulfed by an oxygen-using (aerobic) prokaryotic cell, forming a mutually beneficial symbiotic relationship

Why are mitochondria and chloroplasts considered evidence for the endosymbiotic theory?

they both contain ribosomes and circular DNA

How are cells connected in plants?

plasmodesmata, which are channels connecting cells.

What are the three main types of cell junctions (connections between animal cells)?

tight junctions, desmosomes, gap junctions

What is a tight junction?

the plasma membrane of neighboring cells are tightly pressed against one another, bound together by proteins; creates a seal that does not allow extracellular fluid to cross a layer of epithelial cells (such as skin)

What are desmosomes?

functions like rivets, fastening cells together into strong sheets; anchored by keratin protein filaments; used to attach muscle cells to one another

What are gap junctions?

membrane proteins create pores/channels between cells; most important for communication between cells

What are the main functions of a cell membrane?

controls the movement of substances in and out of cell, allows cells to communicate with one another and interact with their external environment

What is the purpose of sugars in the cell membrane?

acts as ID markers to communicate with other cells

What does amphipathic mean?

has both hydrophobic and hydrophilic regions

What is the role of cholesterol molecules in the phospholipid bilayer?

controls the fluidity of the membrane (depending on temp)

What are channel proteins?

allows for passage of specific molecules or ions through membrane via a channel in the protein

What are carrier proteins?

combines with the molecule or ion to be transported and assist its passage through membrane

Where are peripheral proteins found?

inner membrane surface

Where are integral proteins found?

partially or wholly embedded (transmembrane) in the membrane

What are glycoproteins?

proteins with attached carbohydrate chains

What are glycolipids?

phospholipids with attached carbohydrate chains

Where do glycoproteins and glycolipids get the carbohydrate chains?

the golgi adds the chains after the proteins and lipids are produced by the ER

What is the purpose of sugars in the membrane cell?

acts as ID markers by touch between cells for communication

What do Cell Recognition proteins do?

help cells identify one another

What are receptor proteins?

proteins that are shaped in a way that specific molecules bind to it; allows a cell to respond to signals from other cells.

What are the two ways cells communicate?

touch (carbohydrates on cell membrane) or chemical signals (via hormones, etc)

What qualities does a molecule need to have in order to freely cross the cell membrane?

small, hydrophobic (nonpolar)

• ex. CO₂, O₂, glycerol

What do polar ions and sugars rely on to pass the cell membrane?

transport proteins (such as channel and carrier)

Why is a large surface-area-to-volume ratio advantageous for exchanging molecules in small cells?

cells need a large surface area to exchange enough materials with their surroundings and a small volume for materials to travel quickly within the cell

Which cell would be the most effective at material exchange?

the rectangle

When is a concentration gradient formed?

when the concentration of a particle is higher in one area than in another

A particle moving along (or down) its concentration is moving from an area of (high / low) concentration to an area of (high / low) concentration

*and vice versa

high, low

What is passive transport?

the movement of substances across the cell membrane without the input of energy

What are the three types of passive transport?

diffusion, osmosis, facilitated transport

What is diffusion?

the net movement of molecules down a concentration gradient

What is osmosis?

the diffusion of water across a selectively permeable membrane

What can dissolve both ways across a cell membrane?

water

What is the net movement of water towards?

the side with the lower water concentration

What are aquaporins?

integral membrane proteins that allow water molecules to travel through

What are the three types of solutions?

isotonic, hypotonic, hypertonic

What happens when cells are placed in hypotonic solutions? (What direction does water flow?)

the water flows into the cell

What is turgor pressure in plants? Is it a good thing or bad thing?

when plant cells are placed in hypotonic solutions and absorbs water in the large central vacuole, so much so that it pushes against the plant wall

It is a good thing

If you were looking at DNA inside a cell, what two things would support your claim that the cell is eukaryotic?

linear chromosomes, located inside a nucleus