Cell Organelles and Cytoskeleton Flashcards

Vocabulary flashcards based on lecture notes about cell organelles and the cytoskeleton.

Mitochondria

Double membrane bound organelles involved in providing energy for the cell; the 'energy powerhouse' of the cell and the site of aerobic respiration and ATP generation.

Aerobic Respiration

The process that occurs in the mitochondria, present in all aerobic cells including plant cells, and is the site of ATP generation.

Outer Mitochondrial Membrane

The outer membrane of the mitochondria, which is permeable to molecules up to 10,000 daltons in size.

Inner Mitochondrial Membrane

The inner membrane of the mitochondria, which is far less permeable than the outer membrane and is heavily folded to create cristae.

Cristae

The folds of the inner mitochondrial membrane.

Mitochondrial Matrix

The space inside the inner mitochondrial membrane.

Mitochondrial DNA (mtDNA)

The DNA contained within mitochondria, which codes for rRNAs, tRNAs, and proteins involved in electron transport and ATP synthesis; inherited from the maternal line alone.

Glycolysis

Anaerobic energy production that occurs in the cytoplasm, producing pyruvate.

Krebs Cycle (TCA Cycle)

An aerobic cycle occurring on the mitochondrial inner membrane, utilizing pyruvate from glycolysis.

ATP (Adenosine Triphosphate)

The energy 'currency' of the cell; the bulk of ATP synthesis occurs in the mitochondrion.

Coenzymes (NADH and FADH)

Carry electrons from the Krebs cycle into the electron transport chain.

Electron Transport Chain

A series of protein complexes that transfer electrons from electron donors to electron acceptors via redox reactions, and couples this electron transfer with the transfer of protons (H+) across a membrane.

Proton-Motive Force

Generated when electron transfer in the electron transport chain is coupled to pumping protons across the inner membrane.

ATP Synthase

Uses the energy stored in the proton gradient across the membrane to generate ATP.

Phototrophs

Organisms that convert solar energy to chemical energy in the form of ATP.

Chloroplasts

Organelles in plants and algae where energy transduction (making ATP from light) and carbon assimilation (making energy-rich carbohydrates from inorganic CO2 and H2O) occur; they contain their own DNA and have a three-membrane system.

Porins

Present in the outer membrane of the chloroplast, making the outer membrane highly permeable.

Intermembrane Space (Chloroplast)

The space between the inner and outer membranes of the chloroplast.

Thylakoids

A third membrane system within chloroplasts; flat sac-like structures suspended in the stroma (matrix) and arranged in stacks called grana.

Stroma

The matrix of a chloroplast, containing enzymes that catalyze CO2 fixation and starch synthesis.

Grana

Stacks of thylakoids within a chloroplast.

Chlorophyll

The primary light-gathering pigment held in the thylakoid membrane by its hydrophobic tail.

Calvin Cycle

The pathway for photosynthetic carbon assimilation, where carbon dioxide and water are converted into simple carbohydrates in the chloroplast stroma.

Endosymbiont Theory

Suggests that mitochondria and chloroplasts evolved from early bacterial cells absorbed into proto-eukaryotic cells.

Vacuoles

Single membrane bound sacs within a cell, used for storage and transport in animal cells.

Central Vacuole

In plants, is very large and used mainly in turgor pressure, pushing the plasma membrane against the cell wall.

Lysosomes

Vesicles found only in animal cells that contain a range of proteins important in degradation and recycling cellular components; the interior of the lysosome is acidic and they can be heterophagic or autophagic.

Peroxisomes

Organelles surrounded by a single membrane, involved in generating and degrading H2O2; contain the enzyme catalase which decomposes H2O2 into water and oxygen.

Catalase

An enzyme found in peroxisomes, which decomposes H2O2 into water and oxygen.

Centrosome/ MTOC

The microtubule-organizing center, located near the nucleus, duplicates during mitosis, move apart and forms the mitotic spindle; the minus end of the microtubules lies nearest the centrosome.

Cytoskeleton

Provides internal support for a cell, acts as a 'rail-road' within the cell, and is dynamic; composed of microfilaments, intermediate filaments, and microtubules.

Microfilaments (Actin Filaments)

Concentrated just below the plasma membrane and attach to the membrane via membrane-microfilament binding proteins.

Intermediate Filaments

Filaments that support the nucleus (lamins) and form a network in the cytosol; have varied sub-units.

Microtubules

Originate from the MTOC and are important for cell movement and movement of vesicles and proteins within the cytoplasm; kinesins and dyneins are motor proteins that transport material along the cytoplasmic microtubule network.

Kinesins and Dyneins

Motor proteins that transport material along the cytoplasmic microtubule network.