Biochemistry, Cell Life Cycle, and Tissue Differentiation Flashcards

Flashcards covering key concepts from biochemistry, genetics, cell division, and tissue differentiation based on lecture notes.

Amino Group

The $-NH_2$ portion of an amino acid molecule.

Carboxylic Acid

The $-COOH$ portion of an amino acid molecule.

Dipeptides

Molecules consisting of two linked amino acids.

Polypeptides

Amino acid chains with less defined structure, typically containing fewer than 50 amino acids.

Proteins

Complex amino acid conformations (secondary, tertiary, and quaternary) containing 50 or more amino acids.

Dehydration Synthesis

A reaction where small molecules are joined into large molecules by removing $-H$ from one molecule and hydroxyl ($-OH$) from another.

Hydrolysis

A reaction where water is added to break apart large molecules into smaller units by adding $-H$ and hydroxyl to the split molecules.

Primary Structure

A linear chain of amino acids connected by peptide bonds.

Secondary Structure

The folding of a protein into alpha helixes or beta pleated sheets, stabilized by hydrogen bonds.

Tertiary Structure

The 3D structure of a protein formed by bonds between R-groups, such as disulfide bonds and ionic interactions.

Quaternary Structure

A structure formed when two or more polypeptide chains combine in a regular pattern, such as in insulin.

Fibrous Proteins

Stable, elongated, threadlike structural proteins that are insoluble in water.

Globular Proteins

Spherical, mobile, and water-soluble functional proteins, such as enzymes, antibodies, and hormones.

Denaturation

The destruction of a protein's 3D structure, causing a loss of function; triggered by heat or extreme pH.

Lipids

A class of molecules united by being insoluble in water but soluble in organic solvents like alcohol and acetone.

Triglyceride

The most abundant source of usable energy in the body, composed of three fatty acid chains and one glycerol molecule.

Phospholipids

Lipids with two fatty acid chains and one phosphorus-containing group that form cell membranes.

Steroids

Lipids derived from cholesterol characterized by four interlocking carbon rings.

Arachidonic Acid

The fatty acid found in cell membranes that serves as the source for most eicosanoids.

Glycosidic Bond

A bond formed when a carbon of a cyclic monomer reacts with the $-OH$ of another monomer in carbohydrates.

Glycogen

A polysaccharide used for primary energy storage in the liver and muscles.

Cellulose

A plant polysaccharide with $\beta-1,4-glycosidic$ bonds that humans lack the enzymes to digest.

Interphase

The major period of the cell life cycle where the cell grows, accumulates nutrients, and replicates its DNA.

S Phase

The subphase of interphase where DNA replication occurs, lasting approximately 8 to 10 hours.

G0 Phase

A resting phase where a cell has temporarily or permanently stopped dividing.

Checkpoint

A point in the cell cycle where the cell is signaled to move forward or stop, such as G1, G2, and Metaphase checkpoints.

Autophagy

The process by which unneeded organelles are destroyed due to cellular stress, injury, or age.

Apoptosis

The process of programmed cell death used to dispose of unneeded cells.

Histone Proteins

Globular proteins that package and regulate DNA; methyl groups on them can shut down nearby DNA.

Law of Complementary Base Pairing

The rule stating Adenine ($A$) always pairs with Thymine ($T$) and Cytosine ($C$) always pairs with Guanine ($G$).

Helicase

The enzyme that unwinds and separates double-stranded DNA by breaking hydrogen bonds between base pairs.

DNA Polymerase

The enzyme that positions complementary free nucleotides along template strands to synthesize new DNA strands.

Semi-conservative Replication

DNA replication where each new molecule consists of one old (original) and one new nucleotide strand.

Gene

A biological unit of heredity located in DNA containing instructions for protein synthesis.

Genome

The complete set of genetic instructions, consisting of approximately 3.2 billion base pairs in humans.

Transcription

The stage of protein synthesis where DNA information is encoded into mRNA in the nucleus.

Translation

The stage of protein synthesis where the mRNA sequence is decoded to assemble polypeptide chains at a ribosome.

Genetic Code

The set of rules by which the base sequence of a DNA gene is translated into amino acid sequences.

Codon

A triplet of mRNA bases, such as the start codon AUG, that codes for a specific amino acid.

Anticodon

A UCA triplet on tRNA that recognizes and binds to the mRNA start codon.

Golgi Apparatus

A cellular 'factory' where proteins from the ER are processed, sorted, and packaged for transport.

Glycocalyx

A fuzzy-looking layer of externally facing glycoproteins and glycolipids that serves as identity markers for the cell.

Cell Differentiation

The process by which cells develop specific and distinctive features due to environmental influences on gene expression.

Ectoderm

The primary germ layer that forms the integumentary and nervous tissues.

Mesoderm

The primary germ layer that forms the skeleton and muscles.

Endoderm

The primary germ layer that forms the digestive system.

Pluripotent Stem Cells

Embryonic stem cells that have the potential to become any cell type in the body.

Multipotent Stem Cells

Adult stem cells restricted to becoming cell types within the specific tissue or organ where they reside.

Senescence

Progressive deterioration of bodily functions over time that increases the risk of disease or death.

Telomeres

Protective caps at the ends of chromosomes that shorten with each cycle of DNA replication.

Epithelial Tissue

A primary tissue type characterized by polarity, specialized contacts, and being avascular but innervated.