Biochemistry for Medical Laboratory Sciences: The Cell & Membranes

Vocabulary flashcards covering key cellular components, organelles, bacterial cell features, plant cell structures, and membrane transport concepts from the lecture notes.

Cell

The basic building block of life; contains hereditary material and can replicate.

Cytoplasm

Aqueous cell contents excluding the nucleus; includes cytosol and organelles.

Nucleus

Membrane-bound organelle in eukaryotes that houses DNA and controls cellular activities.

Nucleoid

Region in bacteria where a single circular chromosome resides; not membrane-bound.

Plasma membrane

The phospholipid bilayer surrounding the cell, regulating what enters and leaves and hosting membrane proteins.

Phospholipid bilayer

Two-layer arrangement of phospholipids forming the core structure of the cell membrane.

Membrane proteins

Proteins embedded in the lipid bilayer that mediate transport, signaling, and enzymatic functions.

Ribosome

Protein-synthesizing machines; present in all cells; bacteria have smaller ribosomes than eukaryotes.

Mitochondrion

Organelle that oxidizes fuels to produce ATP, the cell’s energy currency.

Chloroplast

Plant cell organelle that captures light energy to produce ATP and carbohydrates.

Endoplasmic reticulum (ER)

Network of membranous tubules; rough ER has ribosomes; smooth ER synthesizes lipids and metabolizes drugs.

Rough endoplasmic reticulum

ER studded with ribosomes; site of protein synthesis destined for membranes or export.

Smooth endoplasmic reticulum

ER lacking ribosomes; site of lipid synthesis and drug metabolism.

Golgi apparatus

Organelle that processes, packages, and targets proteins for delivery to other organelles or export.

Lysosome

Organelle that degrades intracellular debris.

Peroxisome

Organelle that destroys peroxides and participates in lipid metabolism.

Cytoskeleton

Network of filaments that provides structure and aids movement of organelles.

Nucleolus

Site of ribosomal RNA synthesis inside the nucleus.

Nuclear envelope

Double membrane surrounding the nucleus; separates chromatin from cytoplasm.

Plant cell

Eukaryotic cell with cell wall, chloroplasts, a large central vacuole, and plasmodesmata.

Cell wall

Rigid layer outside the plasma membrane that provides shape and protection in plants and some bacteria.

Starch granule

Storage carbohydrate in plant cells.

Thylakoid

Membrane-bound sacs inside chloroplasts where light-dependent ATP synthesis occurs.

Plasmodesma

Cytoplasmic channels in plant cell walls connecting adjacent plant cells.

Glyoxysome

Peroxisome in plant cells containing glyoxylate cycle enzymes.

Bacterial cell envelope

Exterior structure of bacteria; varies by type (outer membrane in Gram-negative; thick peptidoglycan in Gram-positive).

Outer membrane

The outermost membrane of Gram-negative bacteria; contains lipopolysaccharides.

Peptidoglycan

Polymer forming the bacterial cell wall; thickness differs between Gram types.

Gram-negative bacteria

Bacteria with an outer membrane and a thinner peptidoglycan layer.

Gram-positive bacteria

Bacteria with no outer membrane and a thick peptidoglycan layer.

Pili

Hair-like structures that provide adhesion to surfaces or other cells.

Flagella

Whip-like structures that propel bacteria.

Transport across the cell membrane

Movement of substances across the membrane; regulated by selective permeability.

Selective permeability

Property of membranes that allows some substances to cross easily while restricting others.

Eukaryotic cell

Cell with a nucleus and membrane-bound organelles.