Biology Concepts Flashcards

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Questions and Answers

What is Biology?

The study of life, defined by properties such as metabolism, reproduction, growth and development, and regulation.

How do biologists organize and categorize the diversity of life?

Through emergent properties that arise at each level from the molecular level to the biosphere.

What is a hypothesis in biology?

A prediction or answer to a well-framed question that must be testable and repeatable.

What is the difference between an element and a compound?

An element cannot be broken down into simpler substances by chemical reactions, while a compound consists of two or more different elements in a fixed ratio. Signup and view all the answers

What most influences the chemical properties of a particular atom?

Valence electrons. Signup and view all the answers

What type of chemical bond is found within a single water molecule?

Covalent bond. Signup and view all the answers

What type of bond forms between adjacent water molecules?

Hydrogen bond. Signup and view all the answers

Explain how the product [H+] [OH-] = 10^-14 relates to the pH scale.

It indicates equilibrium in pure water, where [H+] and [OH-] are equal. Signup and view all the answers

Why is carbon referred to as the 'backbone of life'?

Almost all cells contain carbon-based compounds. Signup and view all the answers

What is Carbon's valence?

<ol start="2"> <li></li> </ol> Signup and view all the answers

What are the two types of reactions involving water?

Dehydration reaction and hydrolysis. Signup and view all the answers

What defines all lipids from a chemical standpoint?

They mix poorly with water. Signup and view all the answers

Why are proteins referred to as the 'workhorses of life'?

Because enzymes can perform their functions repeatedly, sustaining cellular processes. Signup and view all the answers

What aspect of DNA makes it unique?

Each chromosome contains one long DNA molecule carrying several hundred or more genes. Signup and view all the answers

What is wrong with the statement, 'Prokaryotic cells typically have a smaller nucleus than eukaryotic cells'?

Prokaryotic cells do not have a nucleus; DNA is concentrated in the nucleoid region. Signup and view all the answers

Why are certain organelles referred to as components of the 'endomembrane system'?

They all function to regulate protein traffic and perform metabolic tasks in the cell. Signup and view all the answers

What does the term 'endosymbiont' mean?

An organism that lives within another organism in a mutually beneficial relationship. Signup and view all the answers

Study Notes

Properties of Life

Biology studies life, characterized by properties such as metabolism, reproduction, growth, development, and regulation.
Living organisms demonstrate behaviors that define life, identifiable through observable actions.

Organization of Life

Biologists categorize life using emergent properties that manifest at different levels from molecules to biospheres.
Each level exhibits unique characteristics that arise from interactions within and between systems.

Biological Investigation

Biologists employ the scientific method, formulating hypotheses as predictions to test questions.
Effective hypotheses must be testable and repeatable, while some questions remain unanswerable through this methodology.

Elements vs. Compounds

Elements are pure substances that cannot be broken down chemically; they consist of only one type of atom.
Compounds are composed of two or more different elements combined in fixed ratios, demonstrating distinct properties.

Valence Electrons and Chemical Properties

Valence electrons, found in the outer shell of an atom, greatly influence an atom's chemical behavior, determining reactivity and bonding.

Types of Chemical Bonds in Water

Within a water molecule, a covalent bond forms between hydrogen and oxygen.
Hydrogen bonds occur between adjacent water molecules, which are weaker than covalent bonds.

pH Scale and Water

The pH scale is derived from the equilibrium of [H+] and [OH-] in pure water, both at 10^-7 under standard conditions.
This balance defines the neutral pH level of water.

Carbon: Backbone of Life

Carbon is essential to life, forming the basis for most cellular compounds due to its ability to form stable bonds with many elements.

Carbon's Valence and Bonding

Carbon has four valence electrons, allowing it to form up to four covalent bonds, enabling complex molecular structures.

Reactions Involving Water

Dehydration reactions join molecules by removing a water molecule, forming covalent bonds.
Hydrolysis is the reverse, breaking bonds between monomers through water addition.

Characteristics of Lipids

All lipids share a common property of being hydrophobic, meaning they do not mix well with water.

Proteins as the "Workhorses of Life"

Proteins, including enzymes, perform essential functions repeatedly, facilitating cellular processes vital for life.

DNA and Heredity

DNA consists of long molecules within chromosomes that carry numerous genes, serving as hereditary material.

Prokaryotic Cells and Nuclei

Prokaryotic cells lack a true nucleus; their DNA is located in a nucleoid, not membrane-bound, differentiating them from eukaryotic cells.

Endomembrane System

The endomembrane system includes the nuclear envelope, ER, Golgi body, and vesicles, highlighting their shared function in regulating protein traffic and metabolic activities.

Endosymbiont Definition

The term "endosymbiont" refers to a symbiotic relationship where one organism lives inside another, significant in the evolutionary origins of organelles like mitochondria and chloroplasts.

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Description

Explore essential concepts in biology with these flashcards that cover the properties of life and the organization of the biosphere. Perfect for students looking to reinforce their understanding of living systems and biological classification. Test your knowledge and enhance your learning experience!