Cell Biology and Genetics

Metaphase Chromosome Features

• Morphological features of a metaphase chromosome do not include the number of chromosomes.
• Morphological features include: banding pattern, centromere position, and chromosome length.

tRNA Transport

• tRNA transports amino acids.

Tertiary Structure of RNA

• Interactions in the tertiary structure of RNA include: formation of non-canonical pairs or triplets, interactions of arm stems with other arm stems, binding of basic proteins or ions that neutralize the negative charge of RNA.
• The creation of an A-type helix is not involved in tertiary RNA structure formation.

Pseudouridine Loop (T-loop) of tRNA

• The key characteristics of the pseudouridine loop (T-loop) are: it contains an unpaired CCA sequence at the 3' end, and the loop does not contain a D-loop or serve as a ribosome binding site.

Neurotransmitter Receptors

• Ionotropic (ion-channel-coupled) receptors are designed for neurotransmitters when a rapid response is needed.

DNA Replication Elongation

• DNA replication elongation becomes irreversible due to the hydrolysis of pyrophosphate (PPi) to inorganic phosphate.

Combinatorial Control of Gene Expression

• Combinatorial control of gene expression involves groups of transcriptional regulators working together to correctly regulate gene expression. It does not involve a single regulator or operons only.

Mitogen-activated Protein Kinase (MAPK)

• MAPK is the final serine-threonine kinase after the previously activated Ras protein.

Glycoprotein Components

• Glycoproteins, apart from protein, can contain oligosaccharides.

Carbohydrates (Subunits >10)

• Carbohydrates composed of more than 10 subunits are called polysaccharides.

HSC Collection

• HSCs (hematopoietic stem cells) are collected via apheresis, using fluorescent antibodies selective for the CD34 surface protein.

Codon-Anticodon Bonds

• Hydrogen bonds form between codon-anticodon bases.

Lipid Bilayer

• The hydrophobic components of a lipid bilayer are contained inside the bilayer.

DNA Repair (MGMT)

• The DNA repair process involving the MGMT protein is direct repair (DR).

Nucleosome Core Histones

• Histone H1 is not part of the nucleosome core; the core consists of H2A, H2B, H3, and H4.

Mitosis Cyclin Concentration

• The concentration of mitotic cyclin (cyclin B) is highest during the M phase (mitosis).

Programmed Cell Death (Apoptosis)

• Programmed cell death (apoptosis) occurs when an intracellular cell-death program is activated.

Basic Amino Acids

• Proteins contain 20 amino acids.

Protein Secondary Structure

• A hydrogen bond between the NH and CO of amino acid residue i and i+3 stabilizes the α-helix secondary structure.

Interphase Phases

• Interphase includes the G1, S, and G2 phases.

Nucleotide Excision Repair

• Nucleotide excision repair involves the unraveling of the double strand around the damaged nucleotide by helicases, cutting the DNA strand on both sides, and synthesis of a new fragment by DNA polymerase.

Chromosome Lengths

• Metacentric chromosomes have arms of equal length.

Chromosome Separation

• Sister chromatids separate in anaphase of mitosis.

Smallest Living Unit

• A cell is the smallest living unit on Earth.

Chromosome Location (Interphase)

• Chromosomes occupy specific areas in the interphase nucleus, not limiting themselves to the nucleolus or becoming intertwined with each homologue.

RNA Structure (Apical Loops)

• Apical loops (hairpins) exist in the secondary structure of RNA.

Membrane Transport (Sodium-Potassium Pump)

• The sodium-potassium pump is a type of primary active transport.

Secondary Lysosome Formation

• A secondary lysosome forms from the fusion of a primary lysosome and a phagosome.

mRNA Attachment to Ribosome

• When mRNA attaches to a ribosome, the large and small ribosomal subunits come together to initiate translation.

Lysosome Functions

• Lysosomes break down carbohydrates, proteins, fats, and nucleic acids. They are not involved in vesicle sorting or Golgi transport.

Heterochromatin in Interphase

• Heterochromatin in interphase stains dark under a microscope and is in a condensed state. It is genetically inactive.

Orphan Receptors

• Orphan receptors are intended for unknown ligands.

Electron Transport Chain Location

• The electron transport chain occurs in the inner membrane of the mitochondria.

Phagosome Formation

• Phagosome formation is associated with phagocytosis, a type of membrane transport.

Interphase DNA Shortening

• Interphase DNA shortens approximately 10,000 times to become metaphase chromosomes.

Aerobic Respiration

• Aerobic respiration requires oxygen for the breakdown of macromolecules to produce energy in the form of ATP.

DNA Condensation (Histone H1)

• Histone H1 is involved in the formation of the 30nm fiber in DNA condensation.

Circulatory System Transport

• The circulatory system transports hormones and neurotransmitters.

Phospholipid Movement

• Lateral diffusion and rotational motion are types of phospholipid movement that, unlike "flip-flop" movement, can be catalyzed by enzymes in the cell membrane.

Codon Definition

• A codon is three nucleotides of RNA or DNA that code for an amino acid.

Start Codon Recognition

• The START codon, during translation initiation in eukaryotes, is recognized by the binding of the small ribosomal subunit, mRNA, and initiator tRNA.

Glycolipid Components

• Glycolipids contain sphingolipids.

DNA Duplex Formation

• A DNA sequence 5’-AAGCCGTT-3’ can form a DNA duplex by pairing with itself at each position.

EDTA Role

• EDTA prevents blood clotting by binding calcium ions.

Midori Green Safety

• Midori Green should be handled with care using gloves and eye protection because it is toxic.

Midori Green Use

• Midori Green stains DNA for visualization in gel electrophoresis.

DNA Helix Structure

• The DNA helix is a double-stranded, right-handed helix.

PCR Denaturation

• The denaturation step in PCR separates the DNA strands by breaking hydrogen bonds.

Mitochondria Function

• Mitochondria generate ATP through cellular respiration.

PCR Annealing Temperature

• Typical annealing temperatures in PCR range from 50-65°C.

Biological Membrane Structure

• Biological membranes consist of a fluid bilayer of phospholipids with embedded proteins.

DNA Composition

• DNA is composed of nucleotides containing a phosphate group, sugar, and nitrogenous base.

Agarose Composition

• Agarose is a polysaccharide from seaweed.

Lipid Rafts

• Lipid rafts are lipid-rich regions in cell membranes involved in signaling and trafficking.

Chromosome Types

• Chromosomes are categorized as prokaryotic/eukaryotic; metacentric, submetacentric, acrocentric, and telocentric.

Autosomes/Allosomes

• Autosomes are non-sex chromosomes, and allosomes are sex chromosomes.

Mitochondrial Cristae

• Cristae in mitochondria increase the surface area for ATP production.

Centrosome Function

• Centrosomes organize microtubules and form the mitotic spindle.

Kinetochore Function

• Kinetochores attach chromosomes to the spindle during cell division.

Cell Water Content

• Cells are approximately 50-70% water.

PCR Positive Control

• A positive control verifies the PCR process using a known DNA sample.

Stem Cells

• Stem cells have the ability to divide and differentiate into various cell types.

Interphase Definition

• Interphase is the phase when the cell is preparing for division.

Cell Signaling (Junxacrina)

• Cell signaling, in the context of a hypothetical molecule Junxacrina, is a process in which cells regulate their growth in response to outside signals.

Cell Cycle Regulation

• The cell cycle is primarily regulated by cyclin-dependent protein kinases (Cdk) that become active when cyclins attach.

Mitogens

• Mitogens are extracellular signaling molecules that stimulate cell proliferation.

PCR Cycle DNA Copies

• After 6 PCR cycles, there are 64 copies of DNA.

Primary Active Transport

• Primary active transport moves molecules from a low concentration area to a high concentration area using ATP energy.

Totipotent Stem Cells

• Totipotent stem cells can form all cell types and extra-embryonic tissues.

Protein Kinase C (PKC)

• PKC adds phosphate groups to proteins, thereby regulating cellular processes.

DNA Structure

• DNA is a double-stranded molecule composed of nucleotides containing a nitrogenous base, sugar, and phosphate group.

Amino Acid Core Structure

• Amino acids have a central carbon atom bonded to an amino group, carboxyl group, and hydrogen atom, along with a variable side chain.

Amino Acid Backbone (excluding H)

• The amino acid backbone excluding hydrogen atoms looks like N-C-C.

Natural Protein Amino Acids

• Proteins have 20 common amino acids.

RNA Concentration

• The approximate concentration of RNA is 1-5% in a typical cell.

Dominant RNA Type

• rRNA (ribosomal RNA) is the most dominant RNA type in the cell.

Potassium and Sodium Ion Location

• Potassium (K⁺) is mostly concentrated intracellularly, and sodium (Na⁺) is mostly concentrated extracellularly.

Cholesterol Role in Membrane

• Cholesterol modulates membrane fluidity, maintaining stability and flexibility.

PCR Positive Control Purpose

• A positive control verifies that the PCR process works by using a known DNA sample.

Cellular Respiration Purpose

• Cellular respiration breaks down glucose to produce ATP.

Cellular Respiration Sequence

• Cellular respiration follows the sequence of glycolysis → Krebs cycle → electron transport chain.

Carbohydrate Chain Length and Water Solubility

• A longer carbon chain in a carbohydrate makes it less soluble in water.

Carbohydrate Classifications

• Carbohydrates composed of more than 10 molecules are polysaccharides; those with up to 10 are oligosaccharides.

Ribosomes in Cytoplasm

• Free-floating ribosomes in the cytoplasm produce proteins that function inside the cell.

Amyloplast Content

• Amyloplasts primarily contain carbohydrates in the form of starch grains.

First Amino Acid (Mitochondria/Chloroplasts/Bacteria)

• The first amino acid in proteins produced by mitochondria, chloroplasts, and bacteria is N-formylmethionine.

High PCR Annealing Temperature

• A high annealing temperature prevents primer binding to the template.

Cytoplasm Components

• Cytoplasm is primarily composed of water, salts, and organic molecules.

Disulfide Bridges and Protein Structure

• Protein structures with disulfide bridges exhibit tertiary structure.

Double-Ring Nitrogenous Bases

• Adenine and guanine have double-ring (purine) structures.

Single-Ring Nitrogenous Bases

• Cytosine, thymine, and uracil have a single-ring (pyrimidine) structure.

Genetic Code Degeneracy

• Degeneracy of the genetic code means that multiple codons can code for the same amino acid—usually, these codons differ most at the third position.

Thiol-Containing Amino Acid

• Cysteine contains a thiol (-SH) group in its side chain.

Hydroxyl-Containing Amino Acid

• Threonine contains a hydroxyl (-OH) group in its side chain.

Non-polar, Aliphatic Amino Acid

• Leucine has a non-polar, aliphatic side chain.

Cyclic Side Chain Amino Acid

• Proline has a cyclic side chain.

α-Amino Acid Classification (D/L)

• α-amino acids (except glycine) are classified as D or L depending on the orientation of the amino group relative to the chiral carbon in the Fischer projection.

Excitatory Neurotransmitters

• Glutamic acid and aspartic acid are excitatory neurotransmitters.

Serine and Glycine in Lipid Metabolism

• Serine and glycine are involved as precursors in the synthesis of phospholipids.

Amino Acids Involved in Lipid Synthesis

• Serine and glycine are involved in lipid synthesis.

Glutamic Acid in Neuronal Signaling

• Glutamic acid promotes neuronal firing due to its role as an excitatory neurotransmitter.

Hormone Precursor Amino Acid

• Tyrosine is a precursor to hormones, including catecholamines and thyroid hormones.

Tyrosine's Role in Hormone Signaling

• Tyrosine is converted into precursors for hormones, such as catecholamines and thyroid hormones.

Ornithine and Citrulline

• Ornithine and citrulline are intermediate metabolites in the urea cycle.

Inhibitory Neurotransmitter

• γ-Aminobutyric acid (GABA) is a primary inhibitory neurotransmitter.

Peptide Bond Formation Byproduct

• A water molecule is the byproduct of the condensation reaction forming a peptide bond.

Oligosaccharide Attachment in Glycoproteins

• Oligosaccharide chains in glycoproteins are attached to specific amino acid residues through glycosidic bonds—this is covalent.

Commonly Phosphorylated Amino Acids

• Serine and threonine are the most commonly phosphorylated amino acid residues in proteins to form phosphoproteins.

Vitamin Importance

• Vitamins serve as organic coenzymes or prosthetic groups that facilitate biochemical reactions, not as primary energy sources.

Cell Cycle Checkpoint (Chromosome Attachment)

• The M checkpoint ensures that all chromosomes are correctly attached to spindle fibers before separation.

Initiator tRNA in Eukaryotes

• The initiator tRNA in eukaryotes is met-tRNA_iMet.

DNA Polymerase Primer Requirement

• DNA polymerase requires a primer because it only adds nucleotides to an existing strand.

Test your knowledge of cell biology and genetics concepts, including chromosome structure, meiosis, DNA replication, genetic variation, RNA structure, and signaling pathways. This quiz covers key processes involved in cell function and heredity.