Docsity
Docsity
Prepare for your exams
Prepare for your exams

Study with the several resources on Docsity

Earn points to download
Earn points to download

Earn points by helping other students or get them with a premium plan

Guidelines and tips
Guidelines and tips
Sell on Docsity
Sell on Docsity
Docsity AI
Docsity AI
Log inSign up

Prepare for your exams

Study with the several resources on Docsity

Find documents

Prepare for your exams with the study notes shared by other students like you on Docsity

Search for your university

Find the specific documents for your university's exams

Docsity AINEW

Summarize your documents, ask them questions, convert them into quizzes and concept maps

Explore questions

Clear up your doubts by reading the answers to questions asked by your fellow students

Earn points to download

Earn points by helping other students or get them with a premium plan

Share documents
download point icon20 Points

For each uploaded document

Answer questions
download point icon5 Points

For each given answer (max 1 per day)

All the ways to get free points
Get points immediately

Choose a premium plan with all the points you need

Study Opportunities

Choose your next study program

Get in touch with the best universities in the world. Search through thousands of universities and official partners

Community

Ask the community

Ask the community for help and clear up your study doubts

Free resources

Our save-the-student-ebooks!

Download our free guides on studying techniques, anxiety management strategies, and thesis advice from Docsity tutors

Cell Biology: Lecture Notes on Cell Structure and Function, Study notes of Cellular and Molecular Biology

University of Illinois - Urbana-ChampaignCellular and Molecular Biology

These lecture notes cover fundamental concepts in cell biology, including the linnean system of classification, prokaryotic and eukaryotic cells, cell theory, and the structure and function of cellular components such as the plasma membrane, nucleus, mitochondria, and endoplasmic reticulum. The notes also delve into the chemical properties of biological molecules, including carbohydrates and lipids, and their roles in cellular processes. Nucleic acids, including dna and rna, are discussed in terms of their structure and function in information storage and transfer. Finally, the notes cover protein structure and function, emphasizing their diverse roles in movement, defense, structure, transport, signaling, and catalysis.

Typology: Study notes

2024/2025

Uploaded on 09/15/2025

carol-zhang
carol-zhang 🇺🇸

1 document

1 / 12

Toggle sidebar

This page cannot be seen from the preview

Don't miss anything!

bg1
LECTURE 2
Linnean system of classification (made in 1700s) based on physical characteristics - does it
make its own food? Does it move?
- 2 kingdoms wasn’t enough
2 basic types of cells were seen: those with a kernel (eukaryotes) and those without
(prokaryotes)
- Prokaryotes have a nucleoid, cytoplasmic membrane, and cell wall
- Eukaryotes have organelles, distinct compartments within the cell
Until 1977, they only used the prokaryote-eukaryote classification
Then, in 1977 Carl Woese compared sequences of RNAs and found prokaryotes are divided
into eu-bactera and archaea
- Archaea more closely linked to eukarya - archaea more similar to humans than e. Coli!
Cell theory
- Cell is fundamental unit of life
- All organisms made of cells
- Cells come from preexisting cells
Resolution: ability to distinguish between separation of objects close to each other
- Light microscopes -0.2 microns
3.1-3.4 reading
Carbon-carbon and carbon-hydrogen are nonpolar
Hydrogen bonds include H-O, H-N, H-F
- When hydrogen bonds to a highly electronegative atom (electrons love it!)
Isomer: 2 or more molecules with the sane formula, but different structure and characteristics
pf3
pf4
pf5
pf8
pf9
pfa

Partial preview of the text

Download Cell Biology: Lecture Notes on Cell Structure and Function and more Study notes Cellular and Molecular Biology in PDF only on Docsity!

LECTURE 2

Linnean system of classification (made in 1700s) based on physical characteristics - does it make its own food? Does it move?

  • 2 kingdoms wasn’t enough 2 basic types of cells were seen: those with a kernel (eukaryotes) and those without (prokaryotes)
  • Prokaryotes have a nucleoid, cytoplasmic membrane, and cell wall
  • Eukaryotes have organelles, distinct compartments within the cell Until 1977, they only used the prokaryote-eukaryote classification Then, in 1977 Carl Woese compared sequences of RNAs and found prokaryotes are divided into eu-bactera and archaea
  • Archaea more closely linked to eukarya - archaea more similar to humans than e. Coli! Cell theory
  • Cell is fundamental unit of life
  • All organisms made of cells
  • Cells come from preexisting cells Resolution: ability to distinguish between separation of objects close to each other
  • Light microscopes -0.2 microns 3.1-3.4 reading Carbon-carbon and carbon-hydrogen are nonpolar Hydrogen bonds include H-O, H-N, H-F
  • When hydrogen bonds to a highly electronegative atom (electrons love it!) Isomer: 2 or more molecules with the sane formula, but different structure and characteristics

LECTURE 3

Plamsa membrane is selectively permeable

  • Allows cells to maintain a constant internal environment
  • Acts as a selectively permeable barrier
  • Is an interface for cells where information is received from adjacent cells and extracellular signals
  • Has molecules that are responsible for binding and adhering to adjacent cells
  • ‘Oreo cookie’ Nucleus
  • DNA housed in nucleus, must be copied before division
  • Transcription: making RNA from DNA
  • Production of ribosome subunits in the nucleolus Mitochondria
  • Eukaryotes generate ATP in mitochondria Rough ER
  • Ribosomes latch into rough ER, make proteins
  • Secretes proteins into golgi Smooth ER: lipid production, detoxification Golgi apparatus: “post office” that knows where to send proteins Ribosomes: work as a team, read instructions from mRNA (groups of ribosomes bounds to mRNA are called polysomes) LECTURE 4
  • Circularization of carbon takes place with a carbonyl (C=O, either at c1 or c2) and the next-to-last carbon on the chain
  • A-glucose H on top, B-glucose H on bottom
  • aldoses have a carbonyl group at the end of the carbon chain (an aldehyde group), while ketoses have a carbonyl group within the carbon chain (a ketone group)
  • Identical formulas but diff structures are ISOMERS

Oligosaccharides link to other macromolecules, and the cell membrane Glycolipid - sugar and lipid Glycoprotein - sugar and protein Sugars used for signalling!! 🚨 also like a street address, that are on the outside of the cell Carbs can be modified thru addition of chemical groups Polysaccharides Cellulose

  • Plant cell walls
  • Linear unbranced polymers linked by B-1-4 glycosidic linkages
  • “Long spaghetti noodles held together by velcro” (velcro is hydrogen bonding) B 1-4: Yellow highlighted OH’s hydrogen bond with one another (velcro) Starch
  • Energy storage for plants
  • Helical, loosely branched
    • Monomers linked via a-1-
    • Chains branched via a-1- Glycogen
  • Energy storage for animals
  • Highly branched
  • A-1-4 linkages
  • No unbranched glycogens
  • Branches also a-1-6 (same as above photo) LECTURE 5 Lipids
  • Defined by a physical property, not chemical structure
  • Vary widely 4 primary
  • Triglycerides - energy storage
  • Phospholipids and glycolipids (biomembrane composition)
  • Steroids (chemical signaling) Biological lipids
  • Monomers: glycerol (C2H8O3) and fatty acids
  • Glycerol backbone, fatty acid chain
  • Carbon, hydrogen, sulfer have biologically similar electronegativities
  • Oxgyen MUCH HIGHER electronegativity
  • Carbon-hydrogen bonds -> no uneven sharing of electrons -> **NONPOLAR and HYDROPHOBIC Fatty acid naming:
  • Count the carbons
  • Look for c=c double bonds** 16:0 (saturated)

Fatty acid tails can differ too in length and degree of saturation

  • However doesn’t change phospholipid identity Spontaneously form micelles or bilayers Likely interactions between hydrocarbon tails: Covalent bonds and hydrophobic reactions,
  • NOT HYDROGEN BONDS Will fold into micells or bilayers
  • Bilayers have ‘leaflets, one is the c’ Bilayers will fold into lipsomes
  • Outer and inner flaps Some membrane lipids are glycolipids
  • Sphingomyelin is an in between of phispholipids and glycolipids Glycolipids (in green) can have ‘oligosaccharide trees’ on them STEROIDS NOT FOUND IN BACTERIA Cholestrol maintains stability and fluidity Asymmetry in biomembranes
  • Must be EQUAL number of phospholips on eah side of the bilayer, but can be different types
  • Maybe 80% A, 20% B, vs 60% A and 40% B

1st 3 are integral membrane proteins -> removal would disrupt integrity of membrane Peripheral proteins are NOT covalently attached to the membrane Jobs

  • Transport
  • Enzymatic activity
  • Signal transduction
  • Cell-cell recognition
  • Intercellular joining
  • Attachment to the cytoskeleton Lecture 6 Biomembranes are selectively permeable
  • Small and nonpolar (CO2) will zip through
  • Small and polar - polarity will impede, but you’ll get through (H2O)
  • Large (glucose) “no thank you”
  • Fully charged, no matter how small you are, you aren’t getting thorugh Biomembranes are fluid
  • Fry and Ediden
  • Mouse cell and animal cell
  • Membranes were stained and ended up intermingling Enzymes end in -ase
  • Flipases and flopases help facilitate transverse diffusion

Nucleoside monophosphate, diphosphate, triphosphate Pyramidines -> single ring (uracil, cytosine, thymine) Purines -> double ring (adenine, guanine) ACG T DNA ACG U RNA Nucleotides differ in DNA and RNA: Deoxyribose lacking a carbon at the 2’ carbon (just H vs OH in ribose)

DNA

  • C and T
  • A and G Every incoming link/nucleotide has to come in with 3 phosphates (nucleoside triphosphates) DNA monomers: “deoxyribonucleoside triphosphate” dNTP Usually double stranded

RNA

  • OH at 2’ carbon of ribose sugar
  • C and U
  • A and G RNA monomers: ribonucleoside triphosphates abbreviated as NTP If -TP molecules dont have a d in front of it, they have ribose as their sugar Polymerization of nucleic acids
  • Condensation reaction: Phosphodiester linkage You need 3 phosphates and ‘pay for the bond’ using one
  • Enzyme called a polymerase will break 2 of them apart You gotta bring in a triphosphate molecule, it's gotta attack the three prime hydroxyl group, which is always gonna be there, because the difference between ribose and deoxyribose isn't what's going on at the three prime carbon, it's what's going on at the two prime carbon. **- LINKS TO THE 3’ CARBON
  • Read from 5’ to 3’ (directionality!)** DNA polymerases and RNA polymerases only work for their respective acids
  • a DNA polymerase won't add a DNA molecule to an RNA chain because it gets there, it examines the end of the chain, feels that two prime molecule, that two prime carbon and says, wait, you've got an oxygen there, that's not for me, and it leaves it alone.

Lecture 7 Proteins function

  • Movement
  • Defense
  • Structure
  • Transport
  • Signaling
  • Catalysis/Regulation/Metabolism Structure of animo acid
  • Central carbon, single H attached to it
  • Amino group (N terminus)
  • Carboxyl group (C terminus)
  • Side chain/R-group Amino acids joined by peptide bonds (covalent, N-terminus joins the C-terminus of the previous acid) 20 naturally occurring amino acids (differ thru R group) 20^2=400 possibilities for dipeptides Amino acid groups Uncharged, but polar (uneven distribution of electrons, like H2O) Uncharged, nonpolar (hydrophobic) Pos + charged (basic) Neg - charged (acidic) Bases are proton acceptors
  • Accepted positively charged protons, that’s what makes them positive Acidic amino acids give up protons
  • Thats what names them negative Primary sequence
  • Linear sequence, N to C terminus, beads on a string
  • No two distinct proteins have the same primary sequence Secondary structure
  • Spontaneous bc of hydrogen bonding
  • Hundreds of hydrogen bonding incredibly strong (like velcro and spaghetti!)
  • Partly negative O and partly pos H
  • Peptide backbone Lecture 8