BIOLOGY 1A03 Study Guide - Winter 2018, Comprehensive Midterm Notes - Genome, Gene, Dna
12 Oct 2018
School
Department
Course
Professor
BIOLOGY 1A03
MIDTERM EXAM
STUDY GUIDE
Fall 2018
1
BIO 1A03
Theme 1
T1M1: Structure of the Cell
Unit 1: Cells in Our Body
• We began as 1 cell (egg + sperm) and then have 10 trillion as an adult
• All of our cells have the same genetic heritage as the original fertilized cell even though they have different
functions
• All of our cells are eukaryotic
Eukaryotic Cells
Prokaryotic Cells
• Plant cells, animal cells, fungi
• Have a nucleus
• Bacteria cells
• Do not have a nucleus
• Body has 10x more bacteria cells than euk. (2-3% of our body mass)
• Human Microbiome: a population of microorganisms/microbes
o Includes prokaryotic bacteria and small eukaryotic organisms
o Approx. 10,000 species of microbes in a healthy human body
Examples:
Streptococcus salivarius
• Upper respiratory tract and oral cavity
• Contributes to the formation of dental plaque
• One of the first microbes to colonize a germ-free newborn's oral cavity and
gastrointestinal tract
Staphylococcus haemolyticus
• On our skin
• If it stays on skin = harmless
• If it gets in body = pathogenic
• Infection leads to activation of the immune system
Bacteroides thetaiotaomicron
• Predominate intestinal bacteria
• Makes enzymes that are useful for breaking down plant material
Unit 2: Phospholipids are the Building Blocks of Membranes
• Cell: membrane bound structure containing macromolecules
4 Macromolecules:
Nucleic Acids (DNA and RNA)
• Make up hereditary material of cell, found in DNA
• The info. encoded in DNA can be converted into functional products of cells
(RNA and eventually protein)
Proteins
• Make up structure elements of the cell (flagellum on bacterium)
• Perform metabolic activities (ribosomes, enzymes)
Polysaccharides or
Carbohydrates
• Important structural component of cell (bacterial capsule, plant cell wall)
• Are sources of stored energy (foods made from wheat/rice)
Phospholipids
• Primary component of cell membrane
• ALL cells are surrounded by cell membranes
• Membranes: separate an internal enviro. from external surroundings
o Allows these two distinct enviros to have different chemical composition
o Protects cells from damaging toxins
o Allows entry of important compounds and disposal of metabolic wastes
find more resources at oneclass.com
find more resources at oneclass.com
2
• Cell membrane is make up of phospholipids that have a hydrophilic surface and hydrophobic core
o Allows for "stacked" lipid bilayers to form
o Are a mosaic of lipids, proteins and carbohydrates
• Phospholipids
o Phosphate group -- glycerol -- fatty acid chain
o Typically, 16 or 18 carbons in a single chain that are connected with single bonds (saturated) or double
bonds (unsaturated)
o Phospholipids are amphipathic, have both hydrophobic and hydrophilic properties
o Often move laterally along the plane of the membrane
Unit 3: Organization of Cell Membranes:
• The amphipathic nature, allows phospholipids to form unique structures
• Lipid Micelles are important for absorption of fat-soluble vitamins and complex lipids
• Phospholipids SPONTANEOUSLY adopt membrane structures WITHOUT USING ENERGY
Fluidity of Cell Membrane is Affected by:
1. Number of hydrocarbons
o Longer chains pack together tighter thus reducing fluidity
2. Double bonds
o Double bonds add kinks/bends in hydrocarbon tail, which prevents the chains from packing tightly this increasing
fluidity
3. Temperature (external enviro factors)
o Higher temperature promotes fluidity
o Lower temperatures decrease fluidity
▪ Cold adapted organisms have more unsaturated phospholipids (i.e. double bonds) in their membrane to
help maintain fluidity
4. Steroids (e.g. cholesterol)
o Make up 50% of molecules found in the membrane
o On it's own phospholipid membrane is TOO fluid, the cholesterol molecules constrain fluidity of the membrane
by packing closely to neighboring phospholipids
o In lower temperatures, cholesterol help maintain fluidity by keeping the phospholipids apart from one another
• Within a membrane, different domains have different degrees of fluidity
o Lipid raft = region of lower fluidity
o Can hold macromolecules together in the membrane
o Gather proteins involved in the same metabolic pathway or a collection of receptors on the surface of the
cell
o The lipid raft region is taller bc of longer phospholipid tails + they're saturated
find more resources at oneclass.com
find more resources at oneclass.com
9
BIOLOGY 1A03 Full Course Notes
Verified Note
9 documents
Document Summary
Eukaryotic cells: plant cells, animal cells, fungi, have a nucleus. Prokaryotic cells: bacteria cells, do not have a nucleus, body has 10x more bacteria cells than euk. (2-3% of our body mass, human microbiome: a population of microorganisms/microbes. Includes prokaryotic bacteria and small eukaryotic organisms: approx. 10,000 species of microbes in a healthy human body. Bacteroides thetaiotaomicron: upper respiratory tract and oral cavity, contributes to the formation of dental plaque, one of the first microbes to colonize a germ-free newborn"s oral cavity and gastrointestinal tract. Infection leads to activation of the immune system: on our skin, predominate intestinal bacteria, makes enzymes that are useful for breaking down plant material. Unit 2: phospholipids are the building blocks of membranes: cell: membrane bound structure containing macromolecules. Unit 3: organization of cell membranes: the amphipathic nature, allows phospholipids to form unique structures, lipid micelles are important for absorption of fat-soluble vitamins and complex lipids, phospholipids spontaneously adopt membrane structures without using energy.
