Biology Flashcards: Phospholipids

Questions and Answers

What are the parts of a phospholipid? Are they polar or nonpolar?

Phospholipids consist of a glycerol molecule, two fatty acids, and a phosphate group; the phosphate group is polar (hydrophilic) and the fatty acid chains are nonpolar (hydrophobic).

How do phospholipids arrange themselves in groups around oil? Around water?

In water, phospholipids arrange with their hydrophobic tails facing each other and their hydrophilic heads facing out.

Where will polar molecules attach to the phospholipids?

Polar molecules attach to the hydrophilic regions of phospholipids that form hydrogen bonds with water.

Where will nonpolar molecules attach to the phospholipids?

Nonpolar molecules interact with the nonpolar tails of phospholipids. Signup and view all the answers

The is attracted to water while the is repelled by water.

head, tail Signup and view all the answers

What are the differences between eukaryotic and prokaryotic cells?

Eukaryotic cells have larger ribosomes, a membrane-bound nucleus, and can be unicellular or multicellular; prokaryotic cells do not have a nucleus and have smaller ribosomes. Signup and view all the answers

What similarities do eukaryotic and prokaryotic cells share?

Both have a lipid bilayer and use DNA for genetic information. Signup and view all the answers

What is a unicellular organism?

An organism made of one cell, such as bacteria or protists. Signup and view all the answers

What is a multicellular organism?

An organism made of multiple cells, such as plants, animals, and fungi. Signup and view all the answers

What is a virus?

A virus is a small collection of genetic code (DNA or RNA) surrounded by a protein coat. It cannot replicate alone. Signup and view all the answers

How does a virus compare to a cell?

Cells have a double-stranded DNA molecule and many strands of single-stranded RNA, while viruses can have various types of genetic material. Signup and view all the answers

What parts do all cells have?

All cells consist of three parts: the cell membrane, the nucleus, and the cytoplasm. Signup and view all the answers

What are cell membranes made of?

Cell membranes are made of glycerophospholipids, which consist of glycerol, a phosphate group, and two fatty acid chains. Signup and view all the answers

What does 'aqueous' mean?

Water-based. Signup and view all the answers

What does 'intracellular' refer to?

Inside the cell. Signup and view all the answers

What is 'extracellular'?

Outside the cell. Signup and view all the answers

What is the fluid mosaic model?

The fluid mosaic model of the plasma membrane describes it as a fluid combination of phospholipids, cholesterol, and proteins. Signup and view all the answers

What do the different parts of cell membranes do?

The principal components protect the cell and mediate cellular processes by regulating materials that enter and exit. Signup and view all the answers

How do large, polar molecules cross the cell membrane?

They need help to pass through because their charge and size make it difficult to cross the nonpolar region of the membrane. Signup and view all the answers

How do large nonpolar molecules cross the cell membrane?

They can pass through the membrane, but it is a slow process. Signup and view all the answers

How do small, polar molecules cross the cell membrane?

Small, polar molecules can often pass through the membrane with some assistance. Signup and view all the answers

Study Notes

Phospholipids

Composed of glycerol, two fatty acids, and a phosphate group modified by an alcohol.
Phosphate group acts as a negatively-charged, polar hydrophilic head, while fatty acid chains represent uncharged, nonpolar hydrophobic tails.

Arrangement in Solutions

In aqueous solutions, phospholipids arrange with hydrophobic tails facing inward and hydrophilic heads facing outward.

Polar Molecule Interactions

Hydrophilic regions of phospholipids form hydrogen bonds with water and other polar molecules, present on both the exterior and interior of the cell.

Nonpolar Molecule Interactions

Nonpolar molecules cluster together, interacting with each other while generally avoiding polar molecules. The hydrophilic heads maintain contact with water, ensuring cell membrane surfaces remain hydrophilic.

Hydrophobic and Hydrophilic Characteristics

The “head” of the phospholipid is water-attracting (hydrophilic), whereas the “tail” is water-repelling (hydrophobic).

Eukaryotic Cells

Feature larger ribosomes, possess membrane-bound nuclei, and can be unicellular or multicellular.

Prokaryotic Cells

Lack a nucleus, contain smaller ribosomes, and are typically unicellular.

Similarities Between Eukaryotic and Prokaryotic Cells

Both have a lipid bilayer and use DNA for genetic information.

Unicellular Organisms

Composed of a single cell and include bacteria and protists.

Multicellular Organisms

Includes plants, animals, and fungi.

Viruses

Consist of genetic material (DNA or RNA) encased in a protein coat; cannot replicate independently and are significantly smaller than cells.

Comparison of Cells and Viruses

Cells contain double-stranded DNA and multiple strands of RNA, while viruses may possess varied forms of genetic material.

Fundamental Parts of All Cells

All cells consist of three main components: the cell membrane, nucleus, and cytoplasm.

Composition of Cell Membranes

Made primarily of glycerophospholipids, which include glycerol, phosphate groups, and fatty acid chains.

Aquaeous Definition

Refers to a water-based environment.

Intracellular vs. Extracellular

Intracellular indicates the inside of the cell, while extracellular refers to the outside.

Fluid Mosaic Model

Describes cell membrane structure as a fluid mix of phospholipids, cholesterol, and proteins with carbohydrates extending from surfaces.

Functions of Cell Membrane Components

Protect intracellular contents, protect against the external environment, and regulate material entry and exit from the cell.

Transport of Large, Polar Molecules

Due to their charge and size, large polar molecules require assistance to cross the nonpolar phospholipid bilayer.

Transport of Large Nonpolar Molecules

Can slowly pass through the membrane, but the process is gradual.

Transport of Small, Polar Molecules

Small polar molecules can typically cross membranes more readily, though specific details were not disclosed.

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Description

Test your knowledge on the structure and behavior of phospholipids with these flashcards. Learn how these molecules are composed and how they arrange themselves in various environments such as oil and water. This quiz is perfect for students studying cell biology or biochemistry.