Biology Chapter 2 Quiz

Water makes up a large portion of a cell's mass. It has a polar structure with hydrogen atoms having a slightly positive charge and the oxygen atom a slightly negative charge.

Inorganic ions are essential for various cell processes. They form a small percentage of the cell's total mass.

Organic molecules, with carbon as their backbone, are essential for the structure and function of cells. They form the majority of the cell's dry weight.

Main source of energy for cells. They can be simple sugars (monosaccharides) or complex sugars (polysaccharides).

Simple sugars are the basic building blocks of carbohydrates. They provide energy and are used to create other cellular compounds.

These sugars are complex carbohydrates, formed by linking multiple simple sugars together. They can store energy or have structural functions.

Lipids are a diverse group of molecules, including fats and oils, that are vital for cell structure, energy storage, and signaling.

Proteins, made up of amino acids, are essential workers in cells. They perform a vast range of functions, from structure to catalysis.

These molecules are essential for cell function, playing roles in energy storage, membrane structure, and cell signaling.

Long hydrocarbon chains with a carboxyl group (COO-) at one end. They are the simplest lipids.

They are hydrophobic (water-repelling) due to their long hydrocarbon chains, which mainly consist of nonpolar C-H bonds.

They are made up of three fatty acid molecules linked to a glycerol molecule.

They are the main components of cell membranes, which are essential for isolating the cell's interior from its surroundings.

They are amphipathic, meaning they have both a hydrophobic (water-repelling) tail and a hydrophilic (water-attracting) head.

They are crucial for cell signaling, acting as steroid hormones such as estrogen and testosterone.

The only non-glyceric phospholipid. They play a vital role in maintaining the structural integrity of cell membranes.

ATP (adenosine triphosphate) is the primary energy currency of cells, providing energy for various cellular processes.

cAMP (cyclic adenosine monophosphate) is a crucial signaling molecule involved in various cellular pathways, transmitting information within cells.

Proteins are the 'workhorses' of cells, carrying out diverse functions based on the instructions encoded in nucleic acids.

Proteins are polymers composed of amino acids, with each amino acid having a unique side chain (R group) that defines its properties.

The 20 different amino acids are grouped based on their side chain properties: nonpolar, polar, basic, and acidic. These properties help them interact with other molecules.

A peptide bond forms between the carboxyl group of one amino acid and the amino group of the next, linking amino acids together to form a polypeptide chain.

A polypeptide chain is a linear sequence of amino acids, typically hundreds to thousands long, forming the backbone of proteins.

The unique sequence of amino acids in a polypeptide determines its structure and function, making each protein specific and specialized.

Molecules that have both hydrophobic and hydrophilic regions, allowing them to interact with both water and lipids.

A type of lipid composed of fatty acids linked to polar head groups containing carbohydrates. They are amphipathic, meaning they have both hydrophobic and hydrophilic regions.

A steroid molecule that is a key component of cell membranes. It has a hydrophobic core and a single hydroxyl group making it amphipathic.

The primary information molecules in cells. They are polymers of nucleotides that encode genetic information and guide protein synthesis.

A nitrogenous base, a phosphate group, and a 5-carbon sugar (deoxyribose in DNA, ribose in RNA). These are the building blocks of nucleic acids.

The process of linking nucleotides together to form a nucleic acid chain. This involves forming phosphodiester bonds between the 5'-phosphate of one nucleotide and the 3'-OH of the next.

A double-stranded molecule where the two strands run in opposite directions. Each strand is made of a sequence of nucleotides linked by phosphodiester bonds, and the two strands are held together by hydrogen bonds between complementary base pairs.

The information contained in DNA and RNA dictates the synthesis of specific proteins.

The sequence of amino acids in a polypeptide chain.

The regular arrangement of amino acids within localized regions of a polypeptide chain, often forming alpha-helices or beta-sheets.

The overall three-dimensional shape of a polypeptide chain, determined by interactions between amino acid side chains.

The arrangement of multiple polypeptide chains (subunits) into a functional protein complex.

Phospholipids form a stable barrier between two aqueous media, representing the basic structure of all biological membranes. These bilayers are composed of two layers of phospholipid molecules, with their hydrophobic tails facing inwards and their hydrophilic heads facing outwards.

These molecules are the fundamental units of all cell membranes. Their defining characteristic is their amphipathic nature, meaning they possess both a hydrophobic tail and a hydrophilic head. This dual nature allows them to spontaneously form bilayers in aqueous environments, essential for creating the membrane barrier that separates the cell's interior from its surroundings.

Membrane fluidity is the ability of lipids and proteins to move laterally within the membrane. It is crucial for membrane function and is influenced by factors such as temperature and lipid composition.

The membranes of the mitochondria can contain a higher proportion of proteins compared to other cell membranes, reaching up to 75% of their mass. This high protein content reflects the vital role of mitochondria in cellular respiration, a process requiring numerous protein-mediated reactions.

Cholesterol is a type of lipid that helps regulate membrane fluidity. It inserts into the phospholipid bilayer, interacting with hydrophobic tails to decrease mobility and increase rigidity. However, at low temperatures, it maintains fluidity.

Integral membrane proteins are embedded directly within the phospholipid bilayer. Transmembrane proteins span the entire membrane, while others may be partially embedded. These proteins are essential for various cell functions, including transport, communication, and enzymatic reactions.

Peripheral membrane proteins are indirectly associated with the lipid bilayer, typically through interactions with integral membrane proteins. They are amphipathic, possessing both hydrophilic and hydrophobic regions. They play roles in signaling pathways and enzymatic processes.

Glycoproteins are membrane proteins modified by the addition of carbohydrates. These sugar chains are exposed on the cell surface, contributing to cell recognition, adhesion, and communication. They play a vital role in immune responses and development.

The selective permeability of biological membranes allows cells to control their internal environment. Small, uncharged molecules can freely diffuse across the membrane, while larger polar molecules and charged ions require specific membrane transporters for passage.

Protein channels function as pores within the membrane, facilitating the passage of molecules based on size and charge. Ion channels allow the specific movement of inorganic ions such as sodium, potassium, calcium, and chloride, playing essential roles in nerve signaling and muscle contraction.

Membrane transporters are proteins embedded within membranes that facilitate the movement of molecules across the lipid bilayer. They bind to specific molecules and facilitate their passage, either passively (down the concentration gradient) or actively (requiring energy).

Lipid-anchored proteins are attached to the membrane by a covalently linked lipid moiety. This anchoring mechanism allows them to interact with the membrane without being embedded within the phospholipid bilayer. They play roles in signaling pathways, cell adhesion, and protein trafficking.