Biology Chapter 3: Cells Overview

The cell membrane is composed of a phospholipid bilayer, cholesterol, and various proteins.

Two layers of phospholipid molecules; polar heads face outwards, tails inwards.

A protein embedded in the cell membrane that allows passage of certain molecules or ions.

Binds to non-steroid hormones, causing internal changes inside the cell (message delivered without entering).

Proteins with attached carbohydrates that identify cells to the immune system.

Cells are small to maintain a high surface area-to-volume ratio, allowing sufficient exchange of materials for metabolic activity.

The cell membrane separates the cell's interior from the environment, controls what enters and exits, transmits signals, and identifies the cell to the immune system.

All living things are made of cells, cells are the basic unit of life, and all cells come from pre-existing cells.

Substances produced by cells and are not part of cells that perform life functions themselves. Eg. fingernails.

The chemical processes needed to stay alive.

The ratio of the surface area of an object to its volume

Specific cells in a living body that perform specialized tasks, having adapted features for specific functions.

The movement of material from high to low concentration without energy needed from the cell.

Movement of substances across a membrane without energy input, following the concentration gradient (high to low concentration).

Movement of substances across a membrane against the concentration gradient (low to high), requiring energy (ATP).

A type of passive transport where molecules move from an area of high concentration to an area of low concentration, until equilibrium is reached.

Bulk transport of large molecules or particles into (endocytosis) or out of (exocytosis) a cell, requiring energy (ATP).

The diffusion of water across a semi-permeable membrane, from an area of high water concentration to an area of low water concentration.

A solution with the same concentration of solutes as the inside of a cell.

A solution with a higher concentration of solutes compared to the inside of a cell.

A solution with a lower concentration of solutes compared to the inside of a cell.

An active transport protein that pumps 3 sodium ions out of the cell and 2 potassium ions into the cell, using ATP.

The pump expels sodium ions, creating a lower concentration of water outside the cell, so water diffuses out, preventing cell swelling.

The pump ensures that the concentration of solutes inside and outside the cell is balanced, preventing the cell from shrinking or bursting.

Increasing the sodium/potassium pump activity expels more ions, making the cell smaller. Decreasing the activity allows sodium ions to diffuse into the cell, making it larger.

Hair-like structures on cell surfaces that help move substances, like transporting eggs down oviducts or mucus in the trachea.

Organelles responsible for energy production in cells, converting food into ATP.

Cellular energy production without oxygen, breaking glucose into pyruvate and producing a small amount of ATP.

Cellular energy production with oxygen, where pyruvate is further broken down in the mitochondria to produce a lot of ATP.

The process of converting chemical energy from food molecules into ATP, the primary energy currency of the cell.

The body's need for additional oxygen after intense exercise to break down accumulated lactic acid.

A byproduct of anaerobic respiration that accumulates in muscles during intense exercise, causing burning sensations.

Fats and proteins can also be broken down and used for energy production, entering the mitochondria to generate ATP.

The nucleus is the control center of the cell. It houses the cell's DNA, which contains the genetic instructions for building and maintaining the cell. The DNA also directs the synthesis of proteins, which carry out the cell's functions.

The nuclear membrane is a double-layered structure that encloses the nucleus. It contains pores that allow certain molecules, such as mRNA and small proteins, to pass through.

Ribosomes are tiny structures responsible for protein synthesis. They read the genetic code carried by mRNA and use that information to assemble amino acids into proteins.

Free ribosomes produce proteins that will be used inside the cell, while membrane-bound ribosomes create proteins that will be exported from the cell or embedded in the cell membrane.

The endoplasmic reticulum (ER) is a network of interconnected membranes that serves as a transport system within the cell. It has two types: smooth ER and rough ER.

Smooth ER lacks ribosomes and is involved in lipid synthesis, while rough ER has ribosomes attached and modifies proteins.

The Golgi apparatus is a stack of flattened sacs that modifies, sorts, and packages proteins. It receives proteins from the ER, processes them, and then packages them in vesicles for transport or export.

Lysosomes contain enzymes that break down waste materials, bacteria, and old organelles. Peroxisomes also contain enzymes and help break down toxins.