BIOL302 Cell & Molecular Biology Midterm Multiple Choice Questions

DNA is the carrier of genetic information in the ______, but it can be present in the cytoplasm in diseased cells

nucleus

DNA is built from four nucleotides (A, T, C, and G), and it forms double helix by ____ ______ of two strands

base pairing

DNA is packaged into chromosomes, which host various numbers of genes and form ______ in the nucleus

territories

_____ is a DNA segment that makes RNA or protein

gene

DNA and histones form nucleosomes, which show _____-__-_-_____ structure in the chromatin

beads-on-a-string

Histone modifications regulate chromatin states, including ________ and _______

heterochromatin, euchromatin

Histone modifications regulates gene activity, and _____ ______ is functionally important

epigenetic regulation

________ _____ are formed during DNA packaging

chromatin loops

DNA replication is ________ and by using one DNA strand as a template to synthesize a new strand

semiconservative

DNA replication begins at the replication origins, and the lagging strands is synthesized in ______ fragments

okazaki

DNA synthesis requires ____ ________, which has both polymerization and proofreading activities

DNA polymerase

The ____ _________ _______ includes primase, ligase, helicase, sliding clamp, clamp loader, and topoisomerase

dna replication machine

The common reactions that create DNA damage include _______ and _______, which cause mutations

depurination, deamination

The ____ ________ of DNA repair includes three key steps: excision, resynthesis, and ligation

basic mechanics

______ causes DNA mutations and mismatch repair avoids DNA mutations

mismatch

Double-strand breaks repair includes ________ ___ ________and _______ ________

nonhomologous end joining, homologous recombination

RNA and DNA are chemically different in compositions of ____ (U vs T) and _____ (ribose vs deoxyribose)

base, sugar

RNA transcription is mediated by ___ ______ and TFs that reorganize the _____ and _______

rna polymerases, promoters, terminators

mRNA is processed by __ _______, __ _______, and ______ (removing introns and stitching exons)

5’ capping, 3’ polyadenylation, splicing

Processed mature RNAs are ______ from the nucleus to the cytoplasm and used for protein translation

exported

Translation from RNA to protein uses _____ ____, and is mediated by _____ and _________ ______

genetic code, trna, aminoacyl-tRNA synthetase

Proteins are made in _______, comprising a large and a small subunit that contain 4 rRNAs and ~80 proteins

ribosomes

Ribosome contains 3 sites: ___ for binding new tRNA, ___ for binding polypeptide chain, and ___ for exiting used tRNA

A, P, E

Functional proteins require folding and post-translational modifications, and proteins are degraded by ______

proteasome

Proteins are folded by forming _______ _____ between amino acids, reversible in different conditions

noncovalent bonds

Protein folding forms various shapes and sizes of proteins, which is important for protein ______

functions

Two common patterns of protein folding are _______ and ______, which can form separate domains in a protein

a-helix, b-sheet

Identical protein subunits can assemble into complex structures, depending on the _____ ____ on the subunit

binding sites

_____ ___ allow proteins to interact with other molecules and execute specific functions

binding sites

Protein modifications (e.g. phosphorylation) can function as ________ _____to control the protein’s behavior

molecular switches

Protein interactions can form “_______ ______” or intracellular ________ to carry out complex functions

protein machines, condensates

Proteins can be separated and studied by various ways, e.g., _______, ________, and _________

centrifugation, chromatography, electrophoresis

Different cell types of a multicellular organism share the same genome, and their nuclei are ____

totipotent

Gene expression can be controlled at various steps, including at _______ and ____-_______ levels

transcriptional, post transcriptional

Genes can be switched on by transcriptional ______ and switched off by transcriptional ______

activators, repressors

Gene activation can occur at a distance and is controlled by combinations of different ______ _______

transcriptional regulators

_________ ______by transcriptional regulators can generate various cell types during development

Combinatorial control

Transcriptional regulators can directly convert one cell type into another or induce forming ______ stem cells

pluripotent

____ ________ and _______ _______are important for regulating cell memory

dna methylation, histone modifications

MicroRNAs, siRNAs, and lncRNAs can regulate gene expression at the ___-______ level

post transcriptional

Comparison of nucleotide sequences regions reveal ____ _____ and evolutionary divergence

high conservation

The human genome is predominantly made of _____ ______ and_____ _____

repetitive sequences, noncoding DNA

Mutation, duplication, exon shuffling, transposition, and horizontal transfer contribute to _____ _____

genome evolution

Many viruses can _____ _____ and integrate the viral genome into the host cell’s genome

reverse transcribe

DNA cloning

cutting vector and target DNA with restriction enzymes and pasting them with DNA ligase

Polymerase chain reaction (PCR)

is used to amplify DNA in vitro and is a powerful tool for many applications

Gene functions can be studied by using

reporter genes, GFP, RNAi, transgenics or editing by CRISPR/Cas9

Recombinant DNA techniques are powerful tools to study

gene structure and function