Cell Bio Exam 1 - Learning Objectives

Two tenants of Cell Theory (w/evidence)

1) all organisms are composed of cells(most basic unit)

-hooke saw cork as cells, animals determined as cells later with animals

2)all cells descend from pre-existing/livng cells

5 Properties common to all forms of life

membranes(besides viruses), genetic info(dna/rna), metabolism(energy), repeatable organization/structure, water-based(liquid in cells), replication (RNA, etc), CHNOPS (most abundant elements

Characteristic features of bacteria

Plasma membrane but no organelle, unicellular(can form colonies), have a cell wall(PEPTIDOGLYCAN), refined genome (simple/no non-coding DNA) - shorter and circular genome, not straight like eukaryotes, ribosomes unique, can have flagella(propellor)

Characteristic features of archaea

Prokaryotic, shorter circular refined genome, cell wall(PSEUDOPEPTIGOGLYCAN), adapted to extremes(acidic, heat, cool, salty), have ribosomes same as eukaryotic, propellor flagella

Define electronegativity. How does it determine formation of ionic vs covalent bonds?

The willingness of an atom to grab an electron to fill its outer octet, right and up are most EN. Ionic bonds are formed by a high difference in EN, because one can overpower and grab the other quite well. Covalent bonds are shared more equally if the EN difference is lower.

Characteristic features of eukaryotes(animal cells)

Nucleus+membrane bound organelles, whip flagella, ribosomes same as archaea, genomes are complex, linear, and longer with noncoding DNA, cooperation in tissues for multicellular species,

Properties adn functions of chloroplast

Makes energy through photosynthesis, double membrane(continuous outer and inner), stroma(like matrix), lumen and inner membrane space

properties and functions of golgi

Protein modification + shipping/relocalization, stack of pancakes, protein vesicles form ER fuses to move through Golgi, Cis side(same as ER), trans side (side further from ER)

properties and functions of lysosome

Cells stomach, where digestion happens. Breaks down food molecules or viruses, cuts covalent bonds with water, contains digestive/hydrolytic enzymes, very acidic

Properties and functions of nucleus

Double membrane with pores - contains genetic materia, condenses DNA, site of replication(DNA→DNA) and transcription (DNA→RNA)

properties and functions of endoplasmic reticulum

Portions of nuclear membrate that expanded

Rough ER: ribosomes on surface, protein synthesis, protein modifications

Smooth ER: no ribosomes, lipid biosynthesis, protein modifications

properties and functions of mitochondria

Makes energy, through oxidative phosphorytation, double membrane without pores, smooth outer membrane, extensively folded inner membrane(Cristae) - more surface area to make more energy enzyme, interior (cytoplasm) called matrix, inner membrance space(between matrix and cell membrane), all environments seperated without holes

Describer the origin of mitochondria and chloroplast and nitroplast and how they differ from other organelles

Endosymbiosis - eukaryote swallowed a prokaryotic cell and it made energy for cell, while nitroplast is able to fix nitrogen from atmosphere into ammonia, like other groups but was swallowed by algae.

1. Why are H bonds affected by temperature?

They aren’t strong, so little changes in heat increase molecular movement, so the bonds are broken easily.

1. Why is water considered to be polar?  Your answer should include a discussion of electronegativity.

Water is polar because the oxygen atom is highly electronegative, so its charge pulls at the molecule as it competes with the small EN charge of the H atoms. Oxygen gains a partial negative charge

1. Why don’t polar molecules interact with non-polar molecules?

Like dissolves like, so the polar molecules have a slight attraction to one another due to their dipoles, which means the nonpolar molecules don’t have anything to be attracted to and can’t mix within.

1. Does a pH of 3 represent more hydrogen ions (protons) or less than a pH of 5?  What is the fold difference?

Acids donate protons, so a highly acidic solution would have a lot of molecules willing to donate H’s, so there are a lot of H’s. The difference is 100fold, because each 1 pH unit is a difference of 10

Four classes of lipids and their function in the cell

Phospholipids - membranes

Triglycerides - fuel reserve, fat droplets, energy

Steroids - signaling molecules(test/estro), membrane componenetts

Carotenoids - pigments that absorb light

Why are phospholipids amphipathic and how would they behave in water

They are both polar and nonpolar, because the head is a polar phosphate group and hydrophilic and the tail is hydrophobic. Because of this, they form micelles and bilayers to protect the fatty acid tails from the water and keep the head exposed to the water.

How does saturation affect melting temp for lipids

Saturated lipids have more regard for temperature, so they have a higher melting point because the saturated tails pack together tightly, so they tend to be more solid and only melt in heat, cis-unsat are all janky and cant stack, so theyre liquid and melt at room temp.

How are glycosidic bonds formed in order to make disaccahrides and polysaccharides

Glycosidic bond forms between C1 and C4 of first and second monosaccharide, then condensation reaction occurs to remove an H20

compare/contrast cellulose, starch, and glycogen

Cellulose has no branching and is b 1,4, and is good rigid wall and has neat fibers. Starch and glycogen are both messier, with branching and a-1,4 and a-1,6, and are good for energy. Glycogen is least dense, starch is more, cellulose is most

Compare/contrast DNA and RNA nucleotides and nucleic acids

DNA Nucleic Acid is deoxyribose, diff base and diff c2

RNA Nucleic Acid is ribose, adds OH group on C#2

DNA nucleotide is phosphate group, pentose sugar(DNA), and nitrogenous base(ATGC)

RNA nucleotide is phosphate group, RNA, and nitrogenous base(AUGC)

Describe each of levels of protein structure

Primary - Linear amino acids,

Secondary - folds/shapes (alpha helix, beta sheet), H-bonds between backbone

Tertiary - Complete folded shape of entire protein

Quaternary - Structure of protein group

How does side chain of an amino acid affect protein structure

12 side chains, chemistry determines properties of AA and protein, there are non-polar(hydrocarbon-based), polar(OH, SH, etc), charged(carboxylic acid/amino), and special.

Nonpolar: must be protected from polar environments

Polar: Will make H-bonds with other polar

Charged: Make ionic bonds when charges are opposite

Special: Ring structure, Glycine, Cysteine, only covalent

Why do factors like mutation heat and pH affect protein strucutre

pH = what proportion is protonated or unprotonated, so pH7:acidic sidechains, pH 3 more acidic, weak acids protonated. pH 10, fewer protons available in environ and unprotonated, so at pH 3 and pH 10, cant make ionic bonds because either too many protons or too many used in bases.,

Heat removed H-bonds and denatures protein

List macromolecule(4), each monomer, location in cell, and role

Lipids Fatty Acid membranes, energy, signaling molecules

Proteins amino acid everything in cell

Carbs monosaccharide energy, signaling molecules, structure, protein activation

Nucleic Acids nucleotide Information, energy

How do “semi-permeable” and “amphipatic” relate to membranes

Semi-permeable membranes are selective, and only allow certain molecules through. In the case of finding homeostasis, some membranes will become selective to allow only H2O thorugh. In an amphipathic lipid membrane, it created a chain needing transport for large polar charge molecules that can’t interact with the non-polar center

Amphipathic is polar and nonpolar, so proteins when exposed to a membrane can only have the polar end in the cytoplasm, while the non-polar section is inside the membrane

1. Describe the fluid-mosaic model of the plasma membrane.  What are some of the environmental or structural factors that affect membrane fluidity?  Explain why each has this effect.

Cholesterol - makes membrane more fluid at low temperatures by spreading out and cant sstack, and less fluid at high temperatures by packing tightly, to permit some membranes more stability at extreme temperatures

Temp - higher temp is more fluid, as h bonds seperate, lower temp is less fluid

FA length - Long FA tails, more interaction, less fluid. Short tails, more fluid

Saturation - more saturated, less fluid, stack. Unsaturated cis, bent, cant stack, less fluid

1. Describe the different functions that membrane proteins might carry out.

Anchor(attatchment to cytoskeleton or ECM), Junction(connection between cells(tunnel)), Cell-cell recognition(coordination in tissue), Receptor/Signalling molecules(binds signalling molecule to receptor), Transport(carriers/channels), enzymes ( catalyzes chemical reactions)

1. How do the chemical properties of a protein determine its interaction with the membrane?  Would you expect to find polar regions of a protein in the interior of a membrane?  Explain.

Polar sections remain on the outside of the membrane, while non-polar sections can be inside, because the membrane is nonpolar interior and polar in cytoplasm with polar, hydrophilic heads.

Compare and contrast simple/passive diffusion, facilitated diffusion, and active transport.  Be prepared to predict the direction of movement under a variety of conditions

Simple - nothing needed, no energy, high to low

Facilitated - no energy, transport needed with channell or carrier, high to low

active - energy, channel or carrier, low to high

1. Describe how electrochemical gradients differ from chemical gradients.  Be prepared to predict the direction and extent of transport under a variety of electrical and chemical conditions.

Electrochemical gradients is a difference in both concentration and charge across the membrane, while chemical gradients are only a difference in concentration with a neutral solute

1. Describe the principle of osmosis.  Be prepared to predict the direction of water movement in a variety of scenarios and the effects it would have on specific cell types.

Diffusion of water across a selectively permeable membrane, moving in own concentration gradient

1. How does selective permeability affect the rate or direction of osmosis? Provide examples/conditions to illustrate your point.

Solutes cant cross but water can, so the rate and direction is determined by the solutes that cant cross, rather than the water. hypo, hyper, iso

1. Compare and contrast the different forms of endocytosis.

Phagocytosis - engulfing an unhealthy cell

Pinocytosis - engulfing a random amount of solution around cell to test for concentrations

Receptor-mediated endocytosis - binding a specific solute triggers engulfing

Properties of covalent bonds? basis of bond and relative strength with example

Based on electron sharing, its the strongest bond and can be polar/nonpolar depending on shape. Backbone of all cellular macromolecules, forming and breaking involves consumption and release of energy

Ionic bond properties , basis, relative strength, with example

Second strongest, based on electrostatic attraction of ions following electron transfer

H-bond properties, basis, and relative strength, with example

Weakest bond, but can be strong in a group. its the connection of atoms by partial charge, using polar covalent bonds (water). Dipole-dipole bonds

Four types of lipids - decribe chemical composition adn properties

Phospholipids: membranes - 2 FA tails, a phosphate group, and glycerol. Amphipathic(polar+nonpolar), micelles and bilayers formed in water(hydropho/phil)

Triglycerides: fuel reserve, fat droplets, energy - 3 FA tails, formed by condensation reaction between glycerol and FA, 10-24 C long, sat and unsat(cis and trans)

Carotenoids: pigment that absorb light - plants, algae, bacteria, B-Carotene, vitamin A activity

Steroids: signalling molecules(test/estro), membrane components(cholesterol), hydrocarbon based, cyclic

How do lipids do SDF with example

Steroids slight changes in functional groups on carbon rings create diff functs, phospholipids both form micelles/bilayers when exposed to water

What do all hexoses have in common, and how do they differ

They all are ordered C, H2, O, and all monosaccharides. Different in position of double bonded O(aldehyde or ketone functional groups), and stearic arrangement of OH groups(glucose and galactose have same formula but reverses C—O )

How do carbs used SDF with example

alpha and beta glycosidic bonds are teh same molecules, but OH is on opposite side. In polysaccharide, carbon connection (1-4 vs 1-6) changes function from fiber to messy (cellulose with no branching, vs starch which can branch)

How do nucleic acids used SDF with example

2 OH on C2 prevents long-term double strands, DNA polymer has nothign on C2, RNA has OH group on C2

Four categories of amino acid side whats, chemical properties adn how they interact with other side chains

How do proteins do SDF with example

Chemical bonds important, heat removed H-bonds, denatures(loses shape/structure) leads to loss of function, like egg white going clear

Changes in pH disrupt ionic bonds, also leads to denatured protein

Sickle Cell anemia - hemoglobin normal cells have Glu-Glu (charged), push apart and lead to folding. Sickle cell has Val Glu, non-polar, so difference in sidechain attraction