Comprehensive Biology: Cell Structure, Genetics, and Metabolism

What are the characteristics of all living things

Order, evolutionary adaptation, regulation, energy processing, growth and development, environmental response, reproduction development

Levels of organization

atom → molecule → organelle → cell → tissue → organ → organ system → organism → population → community → ecosystem → biosphere

Prokaryotes vs eukaryotes

• Prokaryotes: no nucleus or organelles, single-celled organisms

• eukaryotes: nucleus + organelles, multicellular organisms

Three domains of life

Bacteria, Archaea, Eukarya

How has evolution unified all life on earth

all life shares common ancestor - natural selection created diversity

Subatomic particles

• protons (+), in nucleus

• neutrons (0), in nucleus

• electrons (-),in outer rings

Atomic number vs mass vs valence

number = protons/electrons; mass = p(e)+n; valence = outer electrons

Explain covalent, hydrogen, and ionic bonds and their strengths

covalent (np e- >0.4, 0.4-2.0 for p) > ionic (e transfer) > hydrogen

Distinguish Polar vs nonpolar bonds

polar = unequal sharing; nonpolar = equal sharing

Explain the relationship between the polar nature of water and its ability to form hydrogen bonds

water is polar (partial charges)= pass through membrane easily

• Partial positive hydrogen ion in H2O bonds with a partial negative ion (hydrogen bonds)

• Water is a good solvent because of it polarity

Analyze the pH scale

pH < 7 acidic, >7 basic; each unit = 10× H+ change

Buffers

function: resist pH change - balancing it and keeping it from having extreme changes

Why carbon is versatile

4 bonds, forms chains/rings, polar + nonpolar molecules

Four macromolecules

• carbs= energy + support

• lipids= energy

• proteins=support

• Nucleic acids DNA storage

Recognize common carbohydrate monomers and polymers. (Provide examples of important carbohydrates and distinguish between their functions for energy storage or structural building blocks.)

Monosacharids=

• quick energy

• Glucose (animals) and fructose (plants)

Polysacharides=

• Energy storage - starch (plants) and glycogen (animals)

• Structure - Cellulose (plants) and chitin (animals)

Compare and contrast the structure and function of triacylglycerol, phospholipids, and steroids.

Molecule	Structure	Function
Triacylglycerol	Glycerol + 3 fatty acids	Long-term energy
Phospholipid	Glycerol + 2 fatty acids + phosphate (hydrophilic head + hydrophobi tails)	Cell membranes
Steroid	4 fused rings	Hormones (testosterone, estrogen)

Nucleotide composition

phosphate + sugar + base (purine vs pyrimidines)

DNA vs RNA

Feature	DNA	RNA
Sugar	Deoxyribose	Ribose
Base	Thymine	Uracil
Structure	Double-stranded	Single-stranded
Function	Stores genes	Protein synthesis/gene expression

Describe Amino acid structure

• Amino group (NH₂)

• Carboxyl group (COOH)

• Hydrogen

• Variable R-group (side chain)
  ➡ The R-group determines protein shape & function

Describe factors that influence the 3D structure of a protein. (Describe five types of bonding interactions that influence the tertiary structure of a polypeptide. (Why and between which side chains do they occur?)

1. Hydrogen bonds – between polar side chains

2. Ionic bonds – between charged side chains

3. Disulfide bridges – between cysteine side chains

4. Hydrophobic interactions – nonpolar side chains cluster inward

5. Van der Waals forces – weak attractions

➡ Protein shape = function

Why cells are small

large SA:V increases efficiency of diffusion

Eukaryotic structures

nucleus, ER, Golgi, mitochondria, lysosomes, peroxisomes, cytoskeleton

Ribosome function

protein synthesis

Endomembrane system

nuclear envelope, ER, Golgi, vesicles, lysosomes, plasma membrane

Secretory pathway

Rough ER → Golgi → vesicle → membrane → secretion

Endosymbiosis evidence

own DNA, ribosomes, double membranes, binary fission

Three cytoskeletal components

microfilaments, intermediate filaments, microtubules

Phospholipid arrangement

bilayer with tails in, heads out

Fluid mosaic model

fluid membrane with proteins, lipids, carbs

Effect of cholesterol on fluidity

high temp: stabilizes; low temp: prevents freezing

Glycosylation

adding carbohydrates to proteins/lipids for cell recognition

Passes membrane easily

small nonpolar molecules (O₂, CO₂)

Tonicity definitions

hypertonic: shrink; hypotonic: swell; isotonic: no net change

Transport types

diffusion: no protein; facilitated: protein; active: ATP needed

Kinetic vs potential energy

kinetic = motion; potential = stored

Second law of thermodynamics

entropy increases

Endergonic vs exergonic

endergonic requires energy; exergonic releases energy

Enzyme function

lower activation energy

Temperature/pH effect on enzymes

extremes cause denaturation

Competitive vs noncompetitive inhibitors

competitive binds active site; noncompetitive binds allosteric site

How ATP powers reactions

ATP hydrolysis releases energy to drive endergonic reactions

Metabolic pathways

ordered enzyme-controlled reactions

Feedback inhibition

end-product inhibits an early enzyme

Redox reactions

oxidation = loss of electrons; reduction = gain

Goal of respiration

produce ATP

Cellular respiration equation

C₆H₁₂O₆ + 6O₂ → 6CO₂ + 6H₂O + ATP

Stages of respiration

glycolysis, pyruvate oxidation, Krebs cycle, oxidative phosphorylation

NADH & FADH₂

electron carriers

ETC location

inner mitochondrial membrane

Final electron acceptor

oxygen (O₂)

ATP synthase

function: makes ATP using proton gradient

Aerobic vs fermentation

aerobic makes ~30 ATP; fermentation makes 2 ATP

Photosynthesis equation

6CO₂ + 6H₂O + light → glucose + 6O₂

Light reactions vs Calvin cycle

light: ATP + NADPH + O₂; Calvin: sugar

Wavelength & energy

shorter wavelength = higher energy

How pigments capture light

absorb photons → excite electrons

Splitting water

in PSII; supplies electrons, releases O₂

Photosynthesis stage dependence

each stage needs the other

ATP production in respiration vs photosynthesis

both use chemiosmosis + ATP synthase

Cell cycle stages

G1, S, G2, M, cytokinesis

Cell cycle checkpoints

prevent division with DNA or spindle errors

Phases of mitosis

prophase, metaphase, anaphase, telophase

Mitotic spindle function

separates chromosomes

Purpose of meiosis

produce haploid gametes; increase genetic variation

Sources of variation

crossing over, independent assortment, random fertilization

Haploid vs diploid

n = one set; 2n = two sets

Meiosis I vs II

I: homologs separate; II: sister chromatids separate

Mitosis vs meiosis

mitosis: 2 identical diploid; meiosis: 4 unique haploid

Mendel's experiments

monohybrid 3:1; dihybrid 9:3:3:1

Monohybrid cross

3:1 phenotype ratio

Non-Mendelian inheritance

incomplete dominance, codominance, epistasis, polygenic traits

Sex-linked genes

on X chromosome; males more affected

Four inheritance patterns

autosomal dominant, autosomal recessive, X-linked recessive, X-linked dominant

DNA structure

double helix; A-T, G-C

DNA replication model

semiconservative

Base pairing

A-T, G-C

Replication enzymes

helicase unwinds; ligase seals; polymerase extends

Leading vs lagging

leading continuous; lagging Okazaki fragments

Telomerase

function: extends ends of chromosomes

Central dogma

DNA → RNA → protein

Transcription vs translation

transcription = DNA → RNA; translation = RNA → protein

Template vs coding strand

template is read; coding matches mRNA except T/U

Genetic code

read in codons

tRNA function

brings amino acids; has anticodon

mRNA vs tRNA vs rRNA

mRNA = message; tRNA = transfer AA; rRNA = ribosome structure

Silent vs missense vs nonsense

silent: no AA change; missense: AA change; nonsense: STOP

Frameshift mutations

shift reading frame → major change

Germline vs somatic mutations

only germline mutations are inherited