Cell Biology and Protein Synthesis Flashcards

Comprehensive practice flashcards reviewing cellular biology, organelle structure and function, DNA replication, protein synthesis, cell growth, division, and differentiation.

What is an amphipathic molecule?

A molecule that exhibits a difference in polarity between its two ends, resulting in a difference in water solubility.

What is the cell membrane?

The membrane surrounding all animal cells, composed of a lipid bilayer interspersed with various molecules; also known as the plasma membrane.

What is a concentration gradient?

The difference in the concentration of a substance between two regions.

How is diffusion defined?

The movement of a substance from an area of higher concentration to one of lower concentration.

What is the difference between endocytosis and exocytosis?

Endocytosis is the import of material into the cell by formation of a membrane-bound vesicle, while exocytosis is the export of a substance out of a cell by formation of a membrane-bound vesicle.

What is extracellular fluid (ECF)?

Fluid exterior to cells, which includes the interstitial fluid, blood plasma, and fluid found in other reservoirs in the body.

What is facilitated diffusion?

The diffusion of a substance with the aid of a membrane protein.

What is the glycocalyx?

A coating of sugar molecules that surrounds the cell membrane.

What is an integral protein?

A membrane-associated protein that spans the entire width of the lipid bilayer.

What is intracellular fluid (ICF)?

The fluid in the cytosol of cells.

What does it mean for a solution to be isotonic?

The solution concentration is the same as a reference concentration.

How do hypertonic and hypotonic solutions differ?

A hypertonic solution has a higher concentration than a reference concentration, whereas a hypotonic solution has a lower concentration than a reference concentration.

What is osmosis?

The diffusion of water molecules down their concentration gradient across a selectively permeable membrane.

What is the difference between phagocytosis and pinocytosis?

Phagocytosis is the endocytosis of large particles via vesicles made from invaginations of the plasma membrane, while pinocytosis is the endocytosis of fluid.

What is receptor-mediated endocytosis?

Endocytosis of ligands attached to membrane-bound receptors.

What is simple diffusion?

A mechanism of passive transport where molecules move across a cell membrane from the side where they are more concentrated to the side where they are less concentrated.

What is the function of the sodium-potassium pump ($\text{Na}^+/\text{K}^+\text{-ATPase}$)?

It is a membrane-embedded protein pump that uses ATP to move $\text{Na}^+$ out of a cell and $\text{K}^+$ into the cell.

What is the difference between autolysis and autophagy?

Autolysis is the breakdown of cells by their own enzymatic action, whereas autophagy is the lysosomal breakdown of a cell's own components.

What is the role of a centriole?

A small, self-replicating organelle that provides the origin for microtubule growth and moves DNA during cell division.

What is cytoplasm?

The internal material between the cell membrane and nucleus of a cell, mainly consisting of cytosol, within which are all other organelles and suspended materials.

What is cytosol?

The clear, semi-fluid medium of the cytoplasm, made up mostly of water.

What is the endoplasmic reticulum (ER)?

A cellular organelle that consists of interconnected membrane-bound tubules, which may (rough type) or may not (smooth type) be associated with ribosomes.

What is the function of the Golgi apparatus?

A cellular organelle formed by a series of flattened, membrane-bound sacs that functions in protein modification, tagging, packaging, and transport.

What are the three main types of cytoskeletal filaments and their relative thicknesses?

Microfilaments (thinnest, made of actin), intermediate filaments (intermediate thickness, made of keratin), and microtubules (thickest, made of tubulin).

What is a lysosome?

A membrane-bound cellular organelle originating from the Golgi apparatus that contains digestive enzymes.

What is the primary function of a mitochondrion?

To produce cellular energy (ATP); it is bound by a double lipid bilayer.

What is a peroxisome?

A membrane-bound organelle that contains enzymes primarily responsible for detoxifying harmful substances.

What are reactive oxygen species (ROS)?

A group of extremely reactive peroxides and oxygen-containing radicals that may contribute to cellular damage.

What is chromatin?

A substance consisting of DNA and associated proteins.

What is a chromosome?

A condensed version of chromatin.

What is a nucleosome?

A unit of chromatin consisting of a DNA strand wrapped around histone proteins.

What is the function of DNA polymerase?

An enzyme that functions in adding new nucleotides to a growing strand of DNA during DNA replication.

What is the function of helicase?

An enzyme that functions to separate the two DNA strands of a double helix during DNA replication.

What is the nuclear envelope?

A membrane that surrounds the nucleus, consisting of a double lipid-bilayer.

What is the function of the nucleolus?

A small region of the nucleus that functions in ribosome synthesis.

What is a triplet in genetics?

A consecutive sequence of three nucleotides on a DNA molecule that, when transcribed into an mRNA codon, corresponds to a particular amino acid.

What is a codon?

A consecutive sequence of three nucleotides on an mRNA molecule that corresponds to a specific amino acid.

What is an anticodon?

A consecutive sequence of three nucleotides on a tRNA molecule that is complementary to a specific codon on an mRNA molecule.

What is the difference between exons and introns?

Exons are coding regions of an mRNA molecule that remain after splicing, whereas introns are non-coding regions of a pre-mRNA transcript that may be removed during splicing.

What is a spliceosome?

A complex of enzymes that serves to splice out the introns of a pre-mRNA transcript.

What is a proteome?

The full complement of proteins produced by a cell, determined by the cell's specific gene expression.

What is the difference between transcription and translation?

Transcription is the process of producing an mRNA molecule complementary to a gene of DNA, while translation is the process of producing a protein from the nucleotide sequence code of an mRNA transcript.

What is Interphase?

The entire life cycle of a cell, excluding mitosis.

What happens during the S phase of the cell cycle?

DNA replication occurs.

What is the G0 phase?

A phase of the cell cycle usually entered from G1, characterized by long or permanent periods where the cell does not move forward into the DNA synthesis phase.

What are the four main stages of mitosis in order?

Prophase, Metaphase, Anaphase, and Telophase.

What occurs during Prophase?

The nuclear envelope breaks down and chromatin condenses to form chromosomes.

What occurs during Metaphase?

Linear alignment of sister chromatids in the center of the cell along the metaphase plate.

What occurs during Anaphase?

Sister chromatids separate into two new nuclear regions of a dividing cell.

What occurs during Telophase?

Two new daughter nuclei form, preceding cytokinesis.

What is a kinetochore?

A region of a centromere where microtubules attach to a pair of sister chromatids.

What is a cleavage furrow?

A contractile ring that forms around a cell during cytokinesis that pinches the cell into two halves.

What is a somatic cell?

All cells of the body excluding gamete cells.

What defines a totipotent cell?

An embryonic cell that has the ability to differentiate into any type of cell and organ in the body.

How do pluripotent, multipotent, oligopotent, and unipotent cells differ?

Pluripotent cells differentiate into a large variety of cell types; multipotent cells differentiate into types within a given lineage; oligopotent cells differentiate into one of a few possible types; unipotent cells are committed to a single specialized cell type.