Vibha Anand, Cytology, HS

What is the cell theory?

The cell theory is a foundational biological principle that states all living organisms are composed of one or more cells, the cell is the basic unit of structure and function in organisms, and all cells arise from pre-existing cells.

What happens when a cell gets too large?

When a cell gets too large, its surface area to volume ratio decreases, making it inefficient for the cell to transport sufficient nutrients in and waste products out to support its volume. This can lead to the cell dividing, becoming toxic, or dying.

Why is there a limit to how big cells can get?

The limit to cell size is primarily due to the surface area to volume ratio. As a cell grows, its volume increases faster than its surface area. The surface area (cell membrane) is responsible for exchange with the environment, and it eventually becomes insufficient to meet the demands of the larger volume of cytoplasm.

What nutrients go into a cell?

Nutrients that typically go into a cell include glucose (or other simple sugars), amino acids, lipids, water, ions, and oxygen (for aerobic respiration).

What waste products come out of a cell?

CO2, urea, various ions, water. ammonia, uric acid

What is the surface area of a cell?

The surface area of a cell is the total area of its outer boundary, the cell membrane. It is the region through which all materials must pass into and out of the cell.

What is the volume of a cell?

The volume of a cell is the amount of space occupied by the cell's internal contents (cytoplasm and organelles).

What are prokaryotic cells?

Prokaryotic cells are simple, single-celled organisms that lack a membrane-bound nucleus and other membrane-bound organelles. Examples include bacteria and archaea.

What are eukaryotic cells?

Eukaryotic cells are more complex cells characterized by the presence of a membrane-bound nucleus and various membrane-bound organelles (like mitochondria, endoplasmic reticulum, etc.). Organisms like animals, plants, fungi, and protists are made of eukaryotic cells.

What does karyo- mean?

nucleus

What are bacterial cell walls made up of?

peptidoglycan, a polymer consisting of sugars and amino acids

What is the cytoplasm made up of?

cytosol/proteins and water

What shape is the chromosome inside of bacterial cells?

circular

What is the cell membrane?

The cell membrane (or plasma membrane) is a selectively permeable barrier that surrounds the cytoplasm of all cells, regulating which substances can enter and exit the cell.

What does semi-permeable mean?

the membrane allows certain molecules or ions to pass through it by means of active or passive transport, while restricting the passage of others.

What is the bilayer made up of?

a double layer of phospholipid molecules

What do all living cells need to be surrounded by?

fluid

What are embedded in the cell membrane?

many types of protiens

What are enzymes?

biological catalysts, usually proteins, that speed up the rate of specific biochemical reactions within cells without being consumed in the process.

What are ion channels?

pore-forming membrane proteins that help establish and control the flow of ions across the cell membrane, playing a crucial role in cell signaling and transport.

What are transporter proteins?

membrane proteins that move specific substances (like glucose, amino acids, or ions) across the cell membrane, either passively or actively.

What are receptor site proteins?

Receptor site proteins are membrane-bound proteins that bind to specific signaling molecules (like hormones or neurotransmitters) and initiate a cellular response.

What are recognition site proteins?

Recognition site proteins (often glycoproteins or glycolipids) are involved in cell-to-cell recognition, allowing the immune system to distinguish between self and non-self cells.

What are immunosuppressant drugs?

medications that suppress or reduce the strength of the body's immune system, often used to prevent the rejection of transplanted organs or to treat autoimmune diseases.

What are autoimmune diseases?

Autoimmune diseases are conditions in which the body's immune system mistakenly attacks its own healthy tissues and cells, treating them as foreign invaders. Examples include type 2 diabetes, rheumatoid arthritis, and lupus.

What is diffusion?

Diffusion is the passive movement of molecules or particles from an area of higher concentration to an area of lower concentration, down their concentration gradient.

What are the four factors that affect the rate of diffusion?

difference in conc., size of molecules, lipid soluble vs water soluble, temperature