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Artificial Selection: Human selects traits in otf­ Cell Theory: All living things are composed of cell s and come from cells A.. Cell Plasma Membrane: Composed of fluid-like phos­ pholip

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Basic Concepts

Biological Science: The Study of Life

A The Scientific Method: How scientists study biology

I Observe phenomena and formulate testable and

falsifiable (in case they are wrong) hypotheses

2 Test hypotheses, collect data, and analyze statisti­

cally (if necessary)

B What is life')

1 Characteristics: Metabolism, reproduction, growth,

movement, responsiveness, complex organization

Evolution

Concept that all organisms are related to each other by

common ancestry: The unifying theme in biology

A Natural Selection: A mechanism for thc occurrence

of evolution

I Survival of those offspring best adapted to the

conditions in whieh they live:

3 Individuals produce sexually many morc ofl~

spring than could possibly survive

b These otfspring are not identical (in most situa­

tions), but show variations based on genetic dit:

ferences

c Esentially, those individuals with variations

that allow them to survive (i.e., adaptations) to

the age of reproduction can pass their genes on

to the next generation

d Thus, nature is selecting oflspring and shaping

the evolution of species

2 Charles Darwin and Alfred Wallace, 19th century biol­

ogists, (onnulated the concept of natural selection

Organismal Evolution

KI 'IGIX)

PLANTAE FU G

" , " tt

B Artificial Selection: Human selects traits in otf­

Cell Theory:

All living things are composed of cell s and come from cells

A Cell Size: Small to maximize surface area to volume ratio for regulating internal cell environment

B Cell (Plasma) Membrane: Composed of fluid-like phos­

pholipid bilayer, proteins, cholesterol and glycoproteins

Cell (Plasma) Membrane

Phosopholipid

as' glucose, CO" 0 2' etc

3 Organelles: Membrane-bound subunits of cells

protein

C Cell Wall: Outside of cell membrane in some organisms:

composed of carbohydrate (c.g., cellulose or chitin) or carbohydrate derivative (c.g., peptidoglycan)

D Cytoplasm: Material outside nucleus

I Sitc for mctabolic activity

2 Cytosol: Solutions with dissolved substances slIch

with specialized functions

E Cytoskeleton: Supportive and metabolic structurc composed of microtubu1es, microfilaments, and inter­

mediate filaments

Cytoskeleton

Prokaryotic Cells:

Simpler cellular organization with no nucleus or other membrane-bound organelles

F l a ge llum

m

Complex cellular organization

A Membrane: Bound organelks induding the following:

I Nucleus: DN /chromosomes, control cellular ac v- , ities via genes

2 Nucleolus: Located within nucleus site I,)r ribo­

some synthesis

3 Rough endoplasmic reticulum: With ribosomes, involved in protein synthesis

4 Smooth endoplasmic reticulum: Without ribo­ somes, involved primarily in lipid synthesis

5 Golgi apparatus: Packaging center for molecules: carbohydrate synthesis

6 Lysosome: Contains hydroly c enymes 1,,,· intra­ cellular digestion

7 Peroxisome: Involved in hydrogen peroxide synthe­

sis and uegradation

8 Chloroplast: Site of photosynthesis

9 Chromoplast: Non-green pigments

10 Leukoplast: Stores stardl

II Mitochondrion: ATP production

12 Vacuole: General storage and space-filling

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m o t>lh

R i ho , o ml! "

e do plasmic

ret ic lum

Plant Cell

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Pl mcm h

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Energy and Life

O u r Su n

A Meta olism: SC:'ies of chemical reactions involved in

storing (a a olsm) or releasing (catabolsm) c ergy

B Enzymes: Biological catalyst: facilitate meta olic

chemic l reactions by speeding up rates and lowerin

heat requirements

Enzyml' Kinetics

C Adenosine triphosphate (ATP): A high-energy

molecule; energy stored in ATP is released by break­

ing phosphatc-to-phosphate bonds and creating

ade osin diphosphate (ADP) or adenosine

ll1o o hosphak (AM P); ATP is recycled by adding

Energy and ATP

ATP

Sunlight or radiant cnergy is captured by chloroph ll

and carotenoid photopigll1ents (found in cytoplasm in

prokaryotcs and c loroplasts in eukaryotes) in tw

main stcps:

A Light-dependent reactions (Lig t Reactions): The

come from 11,0 : 0 , is a by-product

B Light-independent reactions (Dark Reactions:

L:ncrgized electrons m'c u"1I1sferred to CO, (reduction

C ell Res p iration

cose arc removed (oxidation reactions) in a step-wise

A Glycolysis: Anaerobic process in cytoplasm in which

pyruvtltcs, which arc both three-carbon chains

B Krebs cycle: Aerobic process that ox idizes pyruvates

electrons released durin the previous steps arc used

to concentrate hydrogen ions in one area (of the cell

Cell Transport

Passive Transport

A Relies on thermal e ergy of matter; the cell docs n t

do work: there arc four categories:

I Diffusion: Movement from an area of high to low

concentration

2 Facilitated diffusion: A permease, or mcmbra e

e zyme, carries substance

3 Osmosis: Diffusion across a semi-permeabl membrane

4 Bulk flow: Mass movements of fluids atTected by pressure and solut

Active Transport

A Relies on the cell provid ing en rgy supply; there arc

three categories:

I Membrane pumps: erme se L1sed to move su

stance, usu lly in the opposite direction of diffusion

Membrane Pump -ATP Required

Prl.: S Sllf C applied

to pistlJn t o s i s t upward m ove m e nt

W a t er plu s so lut e

Molecule of solute

•

•

•

•

•

0

Pllll SO ph o lipi ci

bilayer

Ch lestero

& •

•

2 Endocytosis: Materials arc brou ht into cell via:

i Phagocytosis: Solds

ii Pinocytosis: Liquids

"Cell eating" "Cell drinking"

3 Exocytosis: Exp l materials from c ll

Exocytosis Sec ret

v e i cl

Cell Reproduction

Cells reproduce in two steps:

A Mitosis: Division of nuclear material

B Cytokinesis: Division of remaining cellular contents

of th cytop lasm

Cell C ycl e

A Cells go through 4 slag s:

I G, : Active growth and metabolism

2 S : DNA synthesis ancl duplication

3 G, : Sylllilcsis of molecules in preparatio for

cell division

a Stages G, S, & G, above arc collecti\ d)

referred to as Interphase: Interphase chrnmo­

somes nrc referred to as c romatin, a dilrw;e

loosely scattered arra gement of chromosome,

4 M itosis & Cytokin sis:

a Mit tic c romosomes in the M it os i ~;l Cy t o k i ­

nesis stage are highly co densed a d c ikd

and thus distinct

Cell Cycle

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v,

:r: "

"­

«:

uJ l ;

A Prophasl': Chromosomes con ense a d organ­

ize; nuclear membrane and nuclcoli disappear:

spin le a paratus assembled and attac ed [0 ccn­

tromeres of duplicated chromosomes

B Metaphase: Spindles lin up duplicated chromo­

C AnaphaS(': Centromere of each duplicated c romosome

D Telophase: Chromosomcs uncuil: nucleoli reappear:

tNTLRI'H SE PROPltASE MEIAPII \~[

'

p"ir Nucleolus 'pindle lomlation ptndlc pole

ANAP II ASI TELOPII ASE

dcc o nd cn:- in

Two new cells mc genetically identical (i.c clonc~)

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[vir C7/ ~ ~ ) I \ f'!1 !Il'f

Meiosis

Sexual Processes

A Sexual Reproduction: Involves the fusion of genet­

ic material (gametes) from two parental organisms

B To ensure the proper chrolllosomal numbers in

the zygote (fertilized egg), each gamete Illust

have half or haploid (N) of the original diploid

(2N) amount of DNA

C Meiosis: Reduces thc chromosome number by

half and resuits in new genetic combinations in

the gametes

Meiosis - 2 distinct stages

Preceded by Interphase; many meiotic events similar

to mitosis; ditTerences arc noted below

A Meiosis

chro osolllC's '-'

Pr o pha se Mclaplw s c A napha s e I Telopha s e I

1

2 Metaphase I: Ilomologues line up at equator

3 Anaphasc J: Ilomologues separated into two

groups, with e ch group having a mi xture of

maternal and paternal chromosomes

4 Tclophasc I: New haploid nuclei t()rming for

two new dau ghkr cell s

5 Intcrkinesis: No replication of DNA oCUlrs

because each chromosome is still duplicated and

consists of two chromatids (although crossing

over results in some chromatids with maternal and

paternal segmenls)

B Meiosis

Prophase II Metaphase II Anaphase II 11 :Iopha sc II Four

dau g ht e r

*Fo ur ne w c ll" a r c g e n et i c a ll y u niqu e a nd haploid ce l s·

I Prophase I: Chromosomes conlkns.:

2 Metaphase II: Chromosomes line up at equator

3 Anaphasc II: Chromntids of c ch chromosome

arc separated

4 Tclo hase II: Each dau hter ecll li·om Meiosis I

will form two more ce lls for a total of lour c lls

Faunal/Floral Gametogenesis

A.ln animals, meiosis occurs ill germinal tis ues and is

c lled spermatogenesis in males and oogcn.:sis in

B In plants th process is similar cxcc:pt that mitotic

divisions may fol low meiosi 1 0 produce gametes

Gametogcnesis

Plant

I Mi J("i~

Multicellular organism

Introduction

A Genetics: The study of traits and their inheritance

13 19th century biologists believed that traits blended; if blending occurrecl things would become more simi­

lar, not differcnt; Darwin and Wallace stated that variations or differences in offspring were necessary

for natural selection to occur

C Gregor Mcndel provided the most plausible hy oth­

esis for genetics: Mendelian genetics: Two laws

were developed by using statistics to analyze results

of crosses inVOlving distinguishing traits of garden peas

I - Law of Segregation of Alternate Factors

Developed by Mendel using single-trait crosscs

A Single-trait crossbreeding:

1 Two truc-breeding (those that consistently yield the same form when crossed with e ch other) par­

ents (1' , ) but different strains were crossed (e.g.,

round versus wrinkled seed)

2 The offspring (F,) from this cross all showed only one trait (e.g., round seed) and this was called the

dominant trait; the traits from the parents did not blend

3 The F, individuals were crossed with ech other to

produce F individuals

4 3/4 of the F, expressed the dominant trait; 1/4

expressed the trait of the other P, parent (e.g., wrinkled seed) which had not been expressed in

the F, generation and was thus rec ssive

13 Mendel's crosses for single traits can be summarized

as follows: Mendel's I" Law: Segregation of Alternate Factors

I'

Gamet

produced b

Pgeneratio

g l ' ll c ration - , 'IE- AII Gg

Dominant G sks rccssivt' g

Gamete

prod u ( e d

o

n

C Mendel's first conclusio s: Discrete factors (now known as genes) were resp nsible for the tra ils and these factors were paired, separatecl (which oc urs

during meiosis) and re ombined (during fertiliz­

tion); alternate forms of factors or genes exist

call d a eles; th F individuals had two alkles,

their genotype co sisted of a dominant and reces­

sive allele (e.g., Rr with R for round and r for wrin­

kled seed); thus, the F,'s wcre h brids; their pheno­

typ.: was similar to only onc of ori inal parent

Mendel Updat d

A Genes arc und on chromosom , and th s ll1ultiple

traits assort independently as lo g as they are locat­

ed on dilferent chromosomes; Mendel studied traits

In peas that were each on separate chromosom ;

gcnes on the same chromosome arc linked and thus

wiil not norma y assort independcntly

B I ntcral'tions bctween alleles:

I Complete d minance: One all le dominates

another allele

2 Incomplete dominanc : Neither a ele is

ex essed fu Ily

3 Codominance: Both allele arc expressed fully

4 Multi lc alleles: More than two a eles for a gene

G Polygenic inhcritanCl': Many genes conlribute to

a phenotype

7 Pleiotropy: Onc gene cn efleet several ph.:ntycs

8 Environmental influcnces: Where the genotype

and environment interact to form a phen tye

II - Law of Independent Assortment

Developed by Mendel using Illultiple-trait crosses

A Two true-breeding parents of diflc rcnt strains for 1 \\0

traits were cro ed; th F,'s were Ihen cros ed pro­ ducing F individuals

13 The results o crosses involving two traits c n be

summarized as ta llows: Mendel's 2"" Law: Indepcndl'nt Assortment

Gray ,hon-haired

generation

p

Galllctes produc e d by

r,

generation

(alllctcs limB 11) st'grcgaliun uf alleleand inlii\ idual

a S~ ortlllt:nt

fY

, hort "hurt ,h url SllO,'l

G

r

J'" (gSS ( g S, gg SS gg I

'Jo rmal 1\ormal I

( ~ I ;I ) (i r il\ "ln rmal ",,"or m al n

~lh ) rt lon g \ h r t log

r 1 piH ' lInl y C\

It (, L l It (,ra) ,

dlo -hairru J long-haired ''

Normal

J ' It ,hNor rt-hmaiarl ed I long-haired

C Mendel concluded statistc lly thai these r.:sults

occurred because alleles for o e trait or gl:ne did not

atTect the inheritance of alleles for an lher trait

Chromosomes and Sex Determination

A In many animals, special chromosomes determine

B ln hUl11ans, Ihere arc 44 auioso ll1Cs and Iwo sex

chro l11osol11es: X and Y in l11ales, X and ,n

fe ales

Sex Determination

1

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Sex-Linked Traits

nant for maleness; the X contains many genes; if a

di rders

_- H '

_Ow

P

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I

C'= I" -w-- -11 ' ,

' , _ - II -­

o

0=

p-o-I

o

0= r-o­

cS

-II-­ ~

Genes DNA & Nucleic Acid

A Gene functions:

I To be pre~erved and transmitted

2 To control various biological functions through

the production of proteins (i.e., large, complex

sequences of amino acids) and RNA

B Gene structure; two types of nucleic acids:

I Deoxyrihonucleic acid (DNA)

2 Ribonucleic acid (RNA)

C Nucleotides: The components of nucleic acids; three

subunits:

Nucleotides

H NitrogenoLls

I Sugar (deoxyribose in DNA; ribose in RNA)

2 Phosphate

3 Nitrogenous base (five possible bases)

a In DNA, the nucleic acid of chromosomes, four

nitrogenous bases are tound: Adenine (A), gua­

nine (G), cytosine (e), and thymine (T)

b RNA consists of similar bases, except uracil

(U) replaces thymine (T)

c DNA is a double helix molecule: Similar to a

spiral staircase or twisted ladder, with the sides

tonned by repeating sugar-phosphate groups

11'om each nucleotide, and the horizontal por­

tions (i.e steps) formed by hydrogen bonds

involving A with T or e with G

d Hereditary information: Genes found along

tile linear ~equence of nucleotides in the DNA

molecule

J)NA J)onble Helix

'.I=H,

,0

0=

p-o-C ,

o

t l" , H " cS

'=~-'Ir­

o ~H 2

- o -r= o P

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f=H ,

P

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o

The Central Dogma

A Replication:

I DNA is copied from other DNA by unzipping the hel ix and pairing new nucleotides with the proper bases (i.e., A with T and e with G) on each sepa­

rated side of the original DNA

B Transcription:

I Messenger (m)RNA is copied from DNA by

unzipping a portion of the DNA helix that corre­

sponds to a gene

2 Only one side of the DNA will he transcribed and nucleotides with the proper bases (A with U and e

with G) will be sequenced to build pre-mRNA

3 Sequences of nucleotides called introns arc

removed and the remaining segments called exons

are spliced together

4 The mature mRNA leaves the nucleus to be tran­

scribed by the ribosomes RNA Synthesis/Transcription

C Translation:

I Proteins arc syn­

thesized from

(m)RNA by ribo­

somes (which are composed of

ribosomal

(r)RNA and pro­

teins) which read

from a triplet

eode (i.e., codons) that is universal

2 The ribosomes

instruct transfer (t)RNAs to bring

in specific amino acids in the

sequence dictated

by the mRNA,

which in turn was built based on the

sequence of nucleotides in the

original gene por­

tion of the DNA

Protein Synthesis

I

Trp POlypeptide\

Mutations

Any random, permancnt change in the DNA molecule;

many are harmful, some have no effect, and a few

actually benefit the organism; nature selects those mutations that are bcneficial or adaptive in organisms

to help shape the course of evolution

Genes in populations versus individuals

A Populations evolve just as do species

B Genotype: Genetic composition of an individual

C Gene Pool: Genetic composition ofa population of indi­ viduals; that is, all alleles for all ge es in a population

D Evolution involves changes in gene pools over time: to

undcrstand changes in gene pools as populations evolve, an understanding of non-evolving popula­ tions is necessary

The Hardy-Weinberg Law

A Both allelic frequencies and genotypic ratios (i.e

gene pools) remain constant from generation to gen­ eration in sexually producing populations, if the fol­

lowing conditions of equilibriul11 exist:

I Mutations do not occur

2 No net 1110vel11ent of individuals out of or into a population occurs

3 All ollspring produced have the same chances for

survival, and mating is random; that is no natural

selection occurs

4 The population is largc so that chance would not

altcr frequencics of alleles

B Algebraic equivalent of the Hardy-Weinberg Law:

1 p" + 2pq + q2 = I where

a p = frequency of dominant allele

b q = frequency of recessive allde

c p2 = AA genotype

d 2pq = Aa genotype

e q2 = aa genotype

C Example:

I If in a group of six individuals there are nine domi­

nant (A) alleles and three reccssive (a) allcles then p

gametes will be produced nine: ofwh ich will hal'c the dOl11inant allelc and three with the n:ccssivc a elc

2 Thc algebraic equation above can be used to predict the ratios of the three possible gcn types as a resull

of 1ertilizations

a Frequency ofAA genotypes is p2 or (0.75)1 = 0.56

b Frequency of Aa genotypes is 2pq or

2(0.75)(0.25) = 0.38

c Frequcncy of an genotypes is q2 or (0.25)2 - 0.06

3 The frequencies of dominant and rccessivc alleles is still

the same thc specific allclcs havc been redislIibuted

Hardy-Weinberg and natural populations

A Few (if any) populations arc in equilibrium:

therdure changes in allele frequcncies and thus genc pools do occur in natural p pulations

B Thc HMdy-Weinberg Law h lps to identify e mec

anisms of these evolutionary changes by predicting that one or more of the four conditions required arc not met; that is:

I Mutations occur

2 Individuals ave and enter populations

3 onrandolll mating and natural sclccti n occur

4 Small populat

Frequency ofa

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