biology AT1

Eukaryotic Cells

Cells that have a distinct nucleus and membrane-bound organelles, such as those in plants, animals, fungi and protozoa.

Prokaryotic Cells

Cells that lack a nucleus and other membrane-bound organelles, typically smaller and simpler than eukaryotic cells, like bacteria.

Diffusion

The process by which molecules move from an area of higher concentration to an area of lower concentration.

Osmosis

A specific type of diffusion concerning water molecules moving across a semi-permeable membrane.

Cell Theory

The fundamental concept that all living organisms are composed of cells, and all cells arise from pre-existing cells.

Photosynthesis

The process by which plants convert light energy, usually from the sun, into chemical energy in the form of glucose.

Cellular Respiration

The metabolic process by which cells convert sugars (like glucose) into energy in the form of ATP, releasing waste products.

Enzymes

Biological catalysts that speed up chemical reactions in cells without being consumed in the process.

Active Transport

The movement of ions or molecules across a cell membrane against their concentration gradient, requiring energy input.

Fluid-Mosaic Model

A description of the cell membrane structure where various proteins are embedded in or attached to a fluid lipid bilayer.

Chloroplasts

Organelles found in plant cells that conduct photosynthesis, converting light energy into chemical energy.

Mitochondria

Known as the powerhouses of the cell, organelles that perform cellular respiration to generate ATP.

Exocytosis

The process of vesicles fusing with the plasma membrane to release their contents outside the cell.

Endocytosis

The process by which cells internalize substances by engulfing them with the plasma membrane.

Surface Area to Volume Ratio (SA/Vol Ratio)

A measurement that explains why cells must remain small; as cells grow, volume increases faster than surface area, challenging efficiency.

Phospholipid Bilayer

The double layer of phospholipids that makes up the cell membrane, with hydrophilic heads facing the outside and hydrophobic tails facing inward.

ATP (Adenosine Triphosphate)

The primary energy carrier in all living organisms, providing energy for cellular functions.

Hydrophilic

Water-attracting; describes the head of a phospholipid that interacts with water.

Hydrophobic

Water-repelling; describes the tail of a phospholipid that avoids contact with water.

What are enzymes?

Enzymes are biological catalysts that speed up chemical reactions in living organisms.

What is the role of enzymes in biological reactions?

Enzymes lower the activation energy needed for reactions to occur, increasing the rate of the reaction.

What factors affect enzyme activity?

Temperature, pH, substrate concentration, and the presence of inhibitors or activators can affect enzyme activity.

What is a substrate in relation to enzymes?

A substrate is the specific reactant that an enzyme acts on during a chemical reaction.

What is the active site of an enzyme?

The active site is the region on the enzyme where the substrate binds, facilitating the chemical reaction.

What distinguishes one cell from another?

Cells can be distinguished by their structure, such as the presence of organelles, cell walls, and their overall shape.

What are the two main types of cells?

Prokaryotic and eukaryotic cells.

What is the fluid mosaic model of the cell membrane?

A model that describes the cell membrane structure as a mosaic of diverse protein molecules floating in or on the fluid lipid bilayer.

What techniques are used to determine a cell’s structure and function?

Various technologies, including microscopy and dye staining, are used to visualize and analyze cell structures.

How do cells regulate material movement?

Cells utilize mechanisms such as diffusion, osmosis, active transport, endocytosis, and exocytosis to move materials in and out.

What is diffusion?

The process by which molecules move from an area of higher concentration to an area of lower concentration.

What is osmosis?

The diffusion of water across a selectively permeable membrane.

What factors affect material exchange across membranes?

Surface-area-to-volume ratio, concentration gradients, and the characteristics of the materials being exchanged.

What are the energy requirements for cells?

Cells require suitable forms of energy, such as light energy and chemical energy from complex molecules.

What are the key biochemical processes in eukaryotic cells?

Photosynthesis, cellular respiration, and the removal of cellular wastes.

How do enzymes function in cells?

Enzymes act as catalysts to speed up biochemical reactions by lowering the activation energy required.

What factors influence enzyme activity?

Environmental conditions like temperature and pH can affect enzyme activity and the rate of reactions.