Biology 1113 Midterm 2

Hypotonic

Water swells the cell due to high ion concentration in the cell

Hypertonic

Water leaves the cell, making it shrink due to small amount of ions inside

Isotonic

No net movement of water with same concentration of ions

What is cell size limited by?

Surface area to volume ratio and diffusion

How do surface are and volume compare?

Surface area grows slower than volume as it gets bigger

The bigger the cell

the less surface area making it harder to move molecules

Diffusion

Movement of molecules from an area of higher concentration to an area of lower concentration.

Osmosis

Diffusion of water through a selectively permeable membrane

What does the plasma membrane allow through?

small, non-polar molecules like O2

Which way does water move?

The direction of higher ion/solute concentration

Affects of surface area and volume on cell appearance?

Determines shape and size in different structures.

Transporter proteins

In the cell membrane that transports molecules into and out of the cell

Facilitated Diffusion

Passage of molecules with their concentration gradient and does not require energy

Channel and Carrier proteins

two types of transport proteins specific to molecules

Active transport requires

ATP

Active transport job

Moving molecules against their concentration gradient

Active transport can create what type of gradient?

Electrochemical

Electrochemical gradient

Couples the transport of solutes with their gradient to transport another solute

Two components of electrochemical gradients

Concentration and electrical gradient

What do organelles allow for?

Simultaneous metabolic functions

Two broad categories of cells:

Prokaryotic and Eukaryotic

Eukaryotes have

membrane bound organelles

Prokaryotes generally don't have

membrane bound organelles or a nucleus

What type of cells are more abundant?

Prokaryotes

Two categories of prokaryotes

Bacteria and Archaea

What does the plasma membrane control?

What goes in and out of the cell

What are plasma membranes made of?

Phospholipids, cholesterol, and many proteins and glycolipids

Most organelles are membrane bound and have

similar membrane composition

What happens when a specific protein is needed?

DNA is transcribed to RNA and RNA leaves the nucleus

The message in RNA is translated into an

amino acid sequence (protein) on a ribosome

Ribosomes can be

free or attached to the endoplasmic reticulum

Function of endomembrane system

Production and transport of macromolecules in eukaryotes

What does the rough ER produce?

proteins

What does the smooth ER do?

Modifies/manufactures lipids and has enzymes that detoxify drugs

Golgi apparatus function

modifies, packages, stores, and transports lipids made by Smooth ER

Lysosomes function

Digestion and recycling of bacteria and debris

Where does cellular respiration occur in eukaryotes?

mitochondria

Mitochondria Function

converts stored energy to ATP and has it's own DNA and ribosomes.

Origin of mitochondria

bacteria engulfed by a eukaryotic cell

Mitochondria is inherited from

the maternal side

Chloroplasts

Site of photosynthesis

How are chloroplasts like mitochondria?

They both contain DNA and ribosomes

Cell walls are made of

Cellulose (plants) or peptidoglycan (bacteria)

Proportion of organelles and functions

Some proportions change overtime to accommodate for the difference in cells

What is the nuclear envelope?

double membrane that surrounds the nucleus

Nuclear Pore Complex (NPC)

multiprotein embedded in nuclear envelope to transport nucleotides/proteins in and RNA/proteins out

What can passively diffuse through a nuclear pore?

Small molecules

What do large molecules need to pass through a nuclear pore?

A nuclear localization signal

What system uses "zip code" to move products?

The endomembrane system

Why is the ER signal the first sequence in some amino acids?

It allows ribosomes to bind to it's receptor and synthesize proteins into the ER

Vesicles bud off of the ER and travel to where?

The Golgi apparatus to be modified

What does the Golgi use to sort proteins with?

Molecular tags that bind to receptors

Exocytosis

When a vesicle merges with the plasma membrane

What makes the plasma membrane slightly larger?

Exocytosis

Endocytosis

When the plasma membrane is pinched in to make a vesicle

What makes the plasma membrane smaller?

Endocytosis

Cytoskeleton

Extensive system of fibers

Function of cytoskeleton

Helps cell maintain shape and helps the cell move

What part of a cell are motor proteins associated with?

the cytoskeleton due to being able to move structure along the fibers

True or False: There is normally a layer outside of the plasma membrane?

True. Made of fiber composites like filaments in ground substance

extracellular matrix (ECM)

The substance in which animal cells are embedded, consisting of protein (collagen)

ECM in plants is made of

carbs like cellulose and pectin to make the cell wall

ECM interacts with

the cytoskeleton

Plasmodesmata

channels through cell walls that connect the cytoplasm's of adjacent cells

Gap Junctions (animal cells)

(communicating junctions) provide cytoplasmic channels between adjacent cells

Tight Junctions (animal cells)

Membranes of neighboring cells are pressed together, preventing leakage of extracellular fluid

Desmosomes (animal cells)

(anchoring junctions) fasten cells together into strong sheets. Cells must have the same/complimentary linking proteins

Pathogens

disease causing agents

Viruses

tiny infectious agents that hijack a host cells metabolic machinery; cannot reproduce or do anything with the host cell

What are viruses made of?

Proteins and DNA/RNA. Sometimes lipid or carbs

How do retroviruses work?

uses reverse transcriptase to make DNA from RNA which can be inserted into the genome

What can linger when you have a virus?

The viral DNA can linger in your cells permanentely

Example of a host specific virus

Bacteriophages

Why are viruses host-specific?

Surface protein/carbs on cells and proteins on the virus that correspond together.

Are most bacteria harmless or harmful?

Harmless

How do bacteria reproduce?

asexually through binary fission

How can bacteria introduce new DNA in their genome?

Exchanging plasmids, picking up pieces of DNA from the environment, and DNA from viruses

How do bacteria cause disease?

Normally by releasing enzymes or toxins

Antibiotic function

kill or inhibit bacterial growth

How do antibiotics work?

Attacks specific bacterial components that human cells do not contain to keep us safe

Contributing factor to antibiotic resistance?

Overuse in agriculture, used for non-bacterial infections, and not finishing a full course

How do vaccines work?

The vaccine inserts dead or weakened pathogen or RNA to produce a primary immune response

Energy

the capacity to do work or supply heat

Form of potential energy

chemical energy as found in chemical bonds in carbs in lipids

Potential energy relevant to cells

energy stored in electrical and chemical gradients

Entropy will ____ in a spontaneous reaction?

Increase

Energy is lost in the form of

heat

Spontaneous reactions occur when

without net input of energy. Products have less PE than reactants

Exergonic

releases energy, negative delta G spontaneous

Endergonic

A nonspontaneous chemical reaction, energy is absorbed= positive delta G

Delta G takes into account

change in entropy(Δ S) and change in enthalpy(Δ H)

Coupling of exergonic and endergonic reactions...

uses phosphate groups/electrons to increase potential energy of a reactant

Enzymes bring reactants together

and stabilize the transition state, lowering Ea.

What causes enzymes to change shape in a reaction?

Cofactor, coenzyme, or prosthetic group near active site

Enzyme reaction rates are influenced by

Temperature, pH, Substrate concentration, and inhibitors near or away from the active site

Cell to cell signaling has 2 responses:

regulating protein synthesis or activating proteins already present in the cell

Signaling molecules can only act on

target cells. They have a receptor for that molecule

Example of how receptors can be changed

Using a drug creating less sensitivity to it's purpose lowering effectiveness

Steroid hormones

lipid hormones derived from cholesterol

Nonsteroid hormones

protein or protein-like