Cell Structure and Function

These flashcards cover key concepts about cell structure and function, cellular processes, and metabolic theory essential for understanding human biology.

What is the basic principle of the cell theory?

The cell is the basic unit of life; all living things are made up of cells; new cells arise only from preexisting cells.

Why are cells small?

Cells are small because of their surface-area-to-volume ratio, where smaller cells have a larger surface area compared to their volume.

What limits cell size?

The surface-area-to-volume ratio limits how large a cell can be while remaining efficient and metabolically active.

What is microscopy's role in studying cells?

Microscopy allows us to visualize cells and their structures, aiding in their study.

What is a eukaryotic cell?

A eukaryotic cell has a nucleus and includes animals, plants, fungi, and protists.

What is a prokaryotic cell?

A prokaryotic cell lacks a nucleus and includes two groups of bacteria: eubacteria and archaebacteria.

What is the function of the plasma membrane?

The plasma membrane surrounds the cell and regulates what enters and leaves.

What types of transport can occur across the plasma membrane?

Transport can be passive (e.g., diffusion, osmosis) or active (e.g., active transport requiring energy).

What is facilitated diffusion?

Facilitated diffusion is the transport of molecules across the plasma membrane from higher concentration to lower concentration via a protein carrier.

What is the main function of ribosomes?

Ribosomes are the sites of protein synthesis.

Describe the structure of the nucleus.

The nucleus contains DNA in the form of chromatin, has a nuclear envelope with nuclear pores, and contains a nucleolus that produces ribosomes.

What is the role of mitochondria?

Mitochondria convert chemical energy stored in glucose into ATP through cellular respiration.

Explain endocytosis.

Endocytosis is the transport of molecules into the cell via invagination of the plasma membrane to form a vesicle.

What is exocytosis?

Exocytosis is the transport of molecules outside the cell by the fusion of a vesicle with the plasma membrane.

What are the three main types of junctions between cells?

The three main types are adhesion junctions, tight junctions, and gap junctions.

What do enzymes do in metabolic reactions?

Enzymes speed up the rate of chemical reactions by lowering the energy of activation.

What is glycolysis?

Glycolysis is the process that breaks glucose into two 3-carbon pyruvates and occurs in the cytoplasm of almost every cell type.

What happens during the Krebs cycle?

The Krebs cycle is a cyclical series of enzymatic reactions that completes the breakdown of glucose, producing NADH and ATP while releasing carbon dioxide.

What is the electron transport chain?

The electron transport chain is a series of proteins that transfer electrons and ultimately use oxygen to produce ATP.

What is the ATP cycle?

The ATP cycle is the process in which ATP is broken down into ADP and phosphate for energy, and then reformed when energy is obtained from food.

What is fermentation?

Fermentation is an anaerobic process that occurs when oxygen is not available, allowing glycolysis to continue and producing lactate.