BIO 189 Final Study Guide

A comprehensive set of vocabulary flashcards covering DNA structure, replication, gene expression, cell division, inheritance patterns, and related genetic concepts from Modules 4–7.

Autosomes

• non sex chromsomeschromosomes

• Humans have 44 autosomes

• 2 sex chromosomes XY

diploid

cells with 2 sets chromsomeons (one from each parent)chromosomes

primer

short strand of RNA that provides a starting point for DNA replication

centromere

constriction region of a chromosome, where sister chromatids attach and spindle fibers connect

Sex chromosome

chromosome that determines sex

chromosome number

total number of chromosomes in a species

DNA replication

process of copying DNA before cell division

sister chromatids

identical copies of chromosomes connected by a centromere after replicatiion

chromosomes

threadlike structure of DNA and protein that carry genetic info

DNA sequence

order of nucleotide bases

A-T, C-G

RNA - uses Uracil instead of thymine

somatic cell nuclear transfer (SCNT)

technique where nucleus of somatic cell is transferred into an egg cell without nucleus

Clones

genetically identical organisms or cells from one ancestor

histones

protein around which DNA winds to form chromatin and helps package DNA in nucleus

differentiation

process that cells specialise in structure and function

karyotype

image of organisms chromosome arranged in homologous pair

Shows chromosome number, structure, and abnormalities (e.g., Down syndrome = trisomy 21).

mutation

change in DNA sequence that may affect protein and traits

Erwins Chargaffs rule

• DNA has equal amounts of A=T, C=G

Watson & Creek

• developed double helix model

• explained base pairing and complementary strands

Roslind & Frankin

• Produced x-ray crystallography to show image of DNA helical structure

• provided evidence for watson and creek

Hershey & Chase

used bacteriographs to show DNA, not protein is genetic material

leveled orgranisation of genes: nucleotide components

• DNA - deoxyribose, RNA - ribose

• phosphate group

• nitrogenous base (A,T,C,G, U)

• the base differentiates nucleotides

leveled orgranisation of genes: base paring how they bond

• A-T (2 hydrogen bonds)

• C-G (3 hydrogen bonds)

• bases held together with hydrogen bonds

leveled orgranisation of genes: specific diversity

sequence of bases determine genetic uniqueness of species

Enzymes: DNA helicase

unzips double helix

Enzymes: Primase

lays down DNA primer to start replication

Enzymes: DNA ligase

seals gaps between Okazaki fragments on lagging strand

semiconservative model

each new DNA molecule has one old (parent) strand and one new strand

Steps of DNA replication: Initiation

helicase unwinds DNA, primase lays primer

Steps of DNA replication: Elongation

DNA polymerase adds nucleotides to the growing strand (leading continuous, lagging in fragments)

Steps of DNA replication: Termination

Ligase seals fragments, two identical DNA molecules formthe final stage where replication ends.

Results of DNA replication

2 identical DNA molecules, with 1 new and 1 old strand

Nucleotide Dimers

caused by UV radiation that result in incorrect base pairing, potentially leading to mutations.

Single nucleotide is altered

- point mutation, altering single nucleotide

  Insertion/Deletions

- framshift mutation, part of chromsome or DNA sequence left out

single nucleotide polymorphism (SNP)

- affects proteins involved in DNA replication

codon

3 base sequence on mRNA that code for specific amino acids

Anticodon

3 base sequence on tRNA that pairs with complementry codon on mRNA

genetic code

set of rules by which codons specify amino acids

transcription

process of copying DNA into RNA(mRNA) via RNA polymerase

base pair substitution

mutation where one nucleotide base replaced by another

Transfer RNA (tRNA)

brings amino acids to ribosome during translation

introns

non coding regions of RNA removed during splicing

knockout

experimental technique where a gene is disabled

epigenetic

changes in gene repression caused by chemical modifications, not changes in DNA sequence

messenger RNA (mRNA)

RNA copy of gene that carries coding instructions to ribosome

exons

coding regions of RNA that remain after splicing and are translated

promoter

DNA sequence where RNA polymerase binds to start transcription

gene expression

process of using DNA instruction to make proteins

step 1 transctption - DNA copied into RNA

step 2 translation - mRNA read by ribosomes build proteins

Ribosomal RNA (rRNA)

structural catalytic RNA that makes up ribosomes

genes

segments of DNA that code for proteins or functions of RNA

RNA polymerase

enzyme that builds RNA using DNA as template during transcription

DNA VS RNA

Feature	DNA	RNA
Sugar	Deoxyribose	Ribose
Bases	A, T, C, G	A, U, C, G
Strands	Double-stranded helix	Single-stranded
Function	Stores genetic info	Carries, translates, or forms ribosomal structure
Stability	Stable	Less stable

transcription stages

step 1: initiation - RNA polymerase binds to promoter region with help from transcription factors

step 2: elongation - RNA polymerase adds complementary RNA nucleotides
step 3: termination - RNA polymerase reaches stop signal, transcript released

Transcription differences in pro vs euk

pro - occurs in cytoplasm, transcription and translation coupled, no mRNA processing

euk - occurs in nucleus , mRNA undergoes processing before leaving nucleus

mRNA processing in Euk

• 5′ cap and poly-A tail added.

• Introns removed, exons spliced together.

• Alternative splicing allows one gene to code for multiple proteins.

translation (mRNA, tRNA, rRNA )

translation - read mRNA codons to assmble amino acids into polypeptides (proteins)

mRNA - carry codoons (instructions)

tRNA - deliver amino acids, each has anticodon complementary to mRNA codon

rRNA: organizes translation and catalyzes peptide bond formation

translation steps

step 1: initiation - ribsomes bind mRNA at start codon (AUG)

step 2: elongation - tRNA bring amino acids ; ribosomes link them to peptide bonds

step 3: termination - ribosomes reach stop codon; polypeptides is released

types of mutation: point mutation

substitution : one base replaced, may be silence, missense(wrong amino acid), or nonsence (stop codon)

types of mutation: frameshift

insertion /deletion : shifts reading frame = completely changing protein sequence

beneficial mutation

create new traits that improve survival e.g antibiotic resistance

environmental effect (epignetics) on gene expression

Diet, stress, toxins, UV light, radiation, smoking can alter gene expression without changing DNA sequence.

alleles

different forms of genes

halpoid (n)

cell with one set of chromosome

prophase

first stage of mitosis/meiosis; chromosomes condense, spindles form, nuclear enveloped breaks down

anaphase

stage where sister chromatids (mitosis) or homologous chromosomes (meiosis I) separate and move to opposite poles

homologous chromosome

pair of chromosomes (one from each parent) with the same genes but possibly different alleles

sexual reproduction

invovles meiosis and fertilzation; offspring genetically unique

asexual reproduction

involves mitosis; offspring are clones

interphase

cell cycle phase of growth (G1), DNA replication (S), and preparation for division (G2)

spindle

microtubules structure that separate chromsomes during cell division

cancer

disease of uncontrolled cell division due to mutations in cell cycle

meiosis

2 division process that produces four genetically unique haploid gametes

telophase

final stage of mitosis/ meiosis, chromosomes arrive at polar ends, chromosomes uncoil, nuclear envelope reforms,

cell cycle

ordered sequence of growth, DNA replication and division (interphase + mitosis/cytokinesis)

metaphase

stage where chromosomes align at cell equatorial plates

tumor

mass of aboral, rapidly growing cells

cleavage furrow

indentation in animal cells during cytokinesis

metastasis

spread of malignant cancer cells to other tissues/organsz

zygote

first diploid cell formed when sperm fertilizes eggc

crossing over

exchange of DNA beween homologous chromosomes during prophase I of meiosis ; increase variation

mitosis

division of nucleus producting 2 identical diploid cells

oncogenes

mutated prot-oncogenes = gas pedal leading to uncontrolled cell division and cancer development.

HeLa cells

• Ethical: Cells taken from Henrietta Lacks in 1951 without consent; raised issues of informed consent, ownership, and patient rights.

• Medical: HeLa cells are “immortal” — first human cell line grown indefinitely. Used in polio vaccine, cancer research, genetics, virology, drug testing.

• Historical: Sparked debates in bioethics, leading to stricter human research protections.

benefits of using cell lines

provide consistent, renewable source of human cells for experiments

can be used to study diseases, drugs, genetic process

chromosome movement in cell cycle and mitosis

1. interphase (G1,S,G2) - DNA replication occurs in S; chromosomes not visible, exit as chromatin

2. prophase: chromosomes condense; spindle forms

3. metaphase: chromosmes align at equator (metaphase plate)

4. anaphase: sister chromatids seperate, pulled to oposite

5. teltophase: chromsosme decondense, envelope reforms

6. cytokinesis: cytoplasm divides(cleavage furrow in animals, cell plate in plants

cytoplasmic division plants vs animals

animals - contractile ring of microfilaments tightens = cleavage furrow

plants - vesicles from golgi form cell plate, develops into new cell wall

microtubules : guide vesicles in plants and from spindle fibers in both

cell cycle checkpoints

G1 checkpoint = checks cell ceize, nutrients, DNA damage, growth singals

G2 checkpoint = checks DNA replication completion, DNA integrity

M checkpoint = ensure chromosomes attached to spindle before anaphase

roles of mitosis

maintain chromosome number: DNA doubles (chromatids) but centromere count stays constant = each daughter cell gets same set

growth, tissue repair, asexual reproduction (cloning)

sexual vs asexual reproducción

asexual (mitosis) - 1 parent, 2 identical diploid daughter cells, no variance

sexual (meiosis) - 2 parents, gametes formed (haploid), fertilization restores diploid, genetic variation from crossing over and independent assortment

mitosis vs meisois

mitosis: 1 divsion, 2 diplooid cells, no cell cerossing over

meiosis: 2 divisions, 4 unique haploid gametes, crossing over in prophase I

Crossing Over:

• Exchange of DNA between homologous chromosomes in Prophase I.

• Creates genetic diversity.

aneuploidy

condition of having abnormal number of chromosomes

heterozygoues

having different alleles for a specific gene

pleiotropy

one gene influence multiple other traits

codominance

both alleles fully expressed blood type

homozygous

identical alleles

polygenic inheritence

traits controled by many genes (height,skin colour)

dihybrid cross

genetic cros tracking of two traitsm

nondisjunction

failure of chromosomes to separate during meiosis gametes with abnormal chromosome number

polyploidy

more than 2 sets of chromosomes (common in plants)

monohybrid cross

cross tacking 1 trait