BIO1110 Exam II Study Guide: Photosynthesis, Molecular Genetics, Cell Division, and Biotechnology

Comprehensive vocabulary flashcards covering Photosynthesis, DNA replication, Transcription, Translation, Mutations, Gene regulation, the Cell Cycle, Mitosis, Meiosis, Mendelian genetics, and Biotechnology for Exam II BIO1110.

Photosystem

A light-capturing unit located in the thylakoid membrane consisting of a reaction-center complex surrounded by light-harvesting complexes.

Calvin Cycle

The light-independent reactions of photosynthesis that utilize ATP and NADPH produced by the light reactions to fix carbon dioxide into carbohydrates.

5' and 3' Ends

The directional orientations of a nucleic acid strand determined by whether the fifth or third carbon of the ribose or deoxyribose sugar is free with an attached phosphate or hydroxyl group.

Semiconservative DNA Replication

The mechanism of DNA replication in which each newly synthesized double helix is composed of one conserved parental template strand and one newly formed daughter strand.

Template Strand

The specific DNA strand of the double helix that RNA polymerase reads to synthesize a complementary RNA transcript during transcription.

Promoter

A specific sequence of DNA where RNA polymerase binds to initiate transcription.

Primary Transcript

The initial, unedited RNA molecule synthesized directly from the DNA template strand before undergoing post-transcriptional processing in eukaryotic cells.

RNA Processing

The eukaryotic modification of a pre-mRNA transcript, including 5' capping, 3' polyadenylation, and splicing out of introns.

Intron

A noncoding intervening sequence within a eukaryotic pre-mRNA that is removed during RNA splicing.

Exon

A coding region of a eukaryotic pre-mRNA transcript that remains after splicing and is expressed into an amino acid sequence.

Codon

A three-nucleotide sequence in mRNA that codes for a specific amino acid or acts as a start or stop signal during translation.

Transfer RNA (tRNA)

An RNA molecule that carries a specific amino acid to the ribosome and base-pairs with the complementary mRNA codon using its anticodon.

Anticodon

A triplet of nucleotides on a tRNA molecule that base-pairs complementarily with a specific mRNA codon during translation.

Ribosomal RNA (rRNA)

The structural and catalytic RNA component of a ribosome that facilitates the translation of mRNA into protein.

Silent Mutation

A point mutation in DNA that changes a nucleotide without altering the amino acid sequence of the encoded protein.

Missense Mutation

A point mutation in which a single base substitution changes a codon to specify a different amino acid.

Nonsense Mutation

A point mutation that changes an amino-acid-coding codon into a premature stop codon, terminating polypeptide synthesis early.

Frameshift Mutation

A mutation resulting from the insertion or deletion of nucleotides not in multiples of three, shifting the reading frame of the entire downstream sequence.

Differential Gene Expression

The expression of distinct sets of genes by cells with identical genomes, allowing different cell types to develop specialized structures and functions.

Epigenetics

The study of heritable changes in gene expression and cellular phenotype that do not involve alterations to the underlying DNA nucleotide sequence.

DNA Methylation

The addition of methyl groups to DNA bases, typically resulting in chromatin condensation and the long-term repression of transcription.

Histone Acetylation

The enzymatic addition of acetyl groups to histone tails, which loosens chromatin structure and promotes active transcription.

G1 Phase

The first growth phase of interphase during which the cell grows in size, synthesizes proteins, and carries out metabolic tasks before DNA synthesis.

S Phase

The synthesis phase of interphase during which the cell replicates its entire genomic DNA.

G2 Phase

The second gap phase of interphase where the cell completes final preparations, synthesizes spindle proteins, and checks for DNA damage prior to mitosis.

Prophase

The initial stage of mitosis during which chromatin condenses into visible chromosomes, the nucleolus disappears, and the mitotic spindle begins to assemble.

Prometaphase

The stage of mitosis characterized by the breakdown of the nuclear envelope and the attachment of spindle microtubules to chromosomal kinetochores.

Metaphase

The stage of mitosis where chromosomes align along the metaphase plate in the center of the dividing cell.

Anaphase

The mitotic stage where sister chromatids separate into individual daughter chromosomes and migrate toward opposite poles of the spindle apparatus.

Telophase

The final stage of mitosis during which daughter nuclei form at each pole, the nuclear envelope reforms, and chromosomes decondense.

Cytokinesis

The physical division of the cytoplasm into two distinct daughter cells, occurring via a cleavage furrow in animal cells and a cell plate in plant cells.

Proto-oncogene

A normal cellular gene that stimulates cell division and growth under strict regulation in healthy cells.

Oncogene

A mutated, hyperactive version of a proto-oncogene that causes unchecked, excessive cell proliferation leading to cancer.

Tumor Suppressor Gene

A gene whose normal protein product inhibits cell division, repairs damaged DNA, or initiates apoptosis, preventing tumor formation.

Diploid ($2n$)

A cell or organism that possesses two complete sets of chromosomes, one contributed by each parent.

Haploid ($n$)

A cell containing a single set of unpaired chromosomes, typical of gametes produced by meiosis.

Autosomes

Chromosomes that are not directly involved in determining the biological sex of an individual.

Sex Chromosomes

Chromosomes that determine the genetic sex of an organism (such as X and Y in humans).

Homologous Chromosomes

A pair of matching chromosomes having the same length, centromere position, and gene loci, with one inherited from each parent.

Sister Chromatids

Two identical copies of a duplicated chromosome produced during S phase and joined together at a common centromere.

Meiosis I

The first division of meiosis, termed reductional division, in which homologous chromosome pairs are separated.

Meiosis II

The second division of meiosis, termed equational division, in which sister chromatids are separated.

Crossing Over

The reciprocal exchange of genetic material between non-sister chromatids of homologous chromosomes during prophase I of meiosis.

Independent Assortment

The random distribution of maternal and paternal homologous chromosome pairs to opposite poles during metaphase I and anaphase I of meiosis.

Nondisjunction

An error during cell division where homologous chromosomes or sister chromatids fail to separate properly, producing aneuploid gametes or daughter cells.

Aneuploidy

A chromosomal condition in which a cell has an abnormal number of chromosomes, such as having one extra or one missing chromosome.

Allele

Any of the alternative versions of a gene that produce distinguishable phenotypic effects.

Law of Segregation

Mendel's first law stating that two alleles for a heritable character segregate during gamete formation and end up in different gametes.

Law of Independent Assortment

Mendel's second law stating that each pair of alleles segregates independently of any other pair of alleles during gamete formation.

Incomplete Dominance

A pattern of inheritance where heterozygous individuals express a phenotype that is intermediate between the two homozygous parental phenotypes.

Pleiotropy

The ability of a single gene to have multiple, seemingly unrelated phenotypic effects throughout an organism.

Epistasis

A type of gene interaction in which the phenotypic expression of one gene alters or masks the phenotypic expression of a second, independently inherited gene.

Pedigree

A standardized family tree diagram that displays the occurrence and inheritance pattern of specific traits or genetic conditions across generations.

Recombinant DNA

A DNA molecule formed in a laboratory setting by combining genetic material from two or more distinct biological sources.

Vector

A DNA molecule, such as a plasmid or viral genome, used to carry foreign genetic material into a host cell for cloning or expression.

Restriction Enzyme

An endonuclease used in biotechnology that cleaves DNA molecules at specific, recognized nucleotide sequences.

Gel Electrophoresis

A laboratory method that separates charged macromolecules like DNA fragments by size as they migrate through an electric field in an agarose gel.

Chain Termination Sequencing Method

A DNA sequencing method that incorporates modified dideoxynucleotides lacking a 3'-OH group to halt elongation at specific base positions.

Polymerase Chain Reaction (PCR)

An in vitro molecular technique used to rapidly amplify a specific target segment of DNA using repeated cycles of denaturation, annealing, and extension.

CRISPR-Cas9

A gene editing system derived from bacterial immunity that employs a synthetic guide RNA and the Cas9 endonuclease to introduce precise double-stranded cuts in DNA.