Biology 6 Exam 1 - Medium Difficulty

Questions and Answers

What proportion of Earth’s surface is covered in water?

3/4 (correct)

1/4

1/2

2/3

What property of water allows the surface to resist being broken when objects are placed on it?

Cohesion (correct)

Adhesion

Evaporative cooling

High specific heat

Which of the following best describes why ice floats on water?

The bonds in ice are covalent

Ice is a liquid

The crystalline structure of ice is less dense than liquid water (correct)

Ice has a higher density than water

What is the significance of water's high heat of vaporization?

It helps regulate temperatures in areas with high water content. Signup and view all the answers

How does adhesion contribute to plant transpiration?

By facilitating the evaporative loss from plant surfaces Signup and view all the answers

Which statement correctly describes hydrocarbons?

They can vary in length, branching, and double bond positions. Signup and view all the answers

What characteristic differentiates organic molecules from inorganic molecules?

Carbon covalently bound to other atoms. Signup and view all the answers

What property of water is most responsible for the cooling effect when sweat evaporates from skin?

Heat of vaporization Signup and view all the answers

What term refers to a mixture of a liquid and large suspended particles, such as milk?

Colloid Signup and view all the answers

What type of bond is primarily responsible for the unique properties of water?

Hydrogen bonds Signup and view all the answers

Which of the following accurately characterizes prokaryotic cells?

Are unicellular and simpler in structure Signup and view all the answers

What is the primary function of ribosomes in a cell?

Synthesize proteins from genetic material Signup and view all the answers

What main role do peroxisomes play in a cell?

Break down fatty acids and amino acids Signup and view all the answers

Which component of a nucleotide contributes to its directionality?

5' and 3' carbon numbering Signup and view all the answers

What is the purpose of the Golgi apparatus in a cell?

To sort, package, and distribute lipids and proteins Signup and view all the answers

Which step is NOT part of the DNA extraction process?

Sonication of the cell membranes Signup and view all the answers

Why must centrifuges be balanced before operation?

To avoid mechanical failure and potential damage Signup and view all the answers

What is the main difference between rough and smooth endoplasmic reticulum?

Rough ER has ribosomes, smooth ER does not Signup and view all the answers

In terms of structure, what is true about eukaryotic cells?

Contain a nucleus and membrane-bound organelles Signup and view all the answers

Which of the following describes the composition of nucleotides?

Phosphate, sugar, and nitrogenous base Signup and view all the answers

What type of linkage is specific to carbohydrates during the formation of polysaccharides?

Glycosidic linkage Signup and view all the answers

In which structure do hydrogen bonds primarily stabilize the folding of a protein?

Secondary structure Signup and view all the answers

Which components make up a nucleotide in nucleic acids?

Phosphate, sugar, and nitrogenous base Signup and view all the answers

What is a common characteristic of all living cells?

All cells contain DNA Signup and view all the answers

Which of the following statements about viruses is correct?

Viruses cannot multiply without infecting a host cell Signup and view all the answers

What type of bond is formed between glycerol and fatty acids in fats?

Ester bond Signup and view all the answers

Which structure is involved in reducing the activation energy of biochemical reactions?

Enzyme Signup and view all the answers

Which nitrogenous bases are classified as purines?

Adenine and Guanine Signup and view all the answers

What is the correct order of structural levels in proteins from simplest to most complex?

Primary, Secondary, Tertiary, Quaternary Signup and view all the answers

What distinguishes structural isomers from cis-trans isomers?

They differ in the arrangement of atoms in space. Signup and view all the answers

What role does the antheridium play in the gametophyte phase of plants?

It is where sperm are produced. Signup and view all the answers

In the context of plant genetics, what is the primary function of the sporophyte phase?

To produce spores. Signup and view all the answers

What did the Miller Experiment aim to demonstrate?

The synthesis of organic molecules from inorganic compounds. Signup and view all the answers

What distinguishes enantiomers from other isomer types?

They are mirror images that cannot be superimposed. Signup and view all the answers

What characteristic of vascular plants enhances their ability to transport nutrients?

They contain xylem and phloem tissues. Signup and view all the answers

Which of the following macromolecules primarily serves as a source of energy for cells?

Carbohydrates Signup and view all the answers

What is the purpose of having a carbon skeleton in organic molecules?

To serve as a backbone for functional groups. Signup and view all the answers

What is a common property of compounds that contain a hydroxyl (-OH) group?

They are known as alcohols and mix well with water. Signup and view all the answers

What defines the process of syngamy in the context of plant reproduction?

Fusion of gametes to form a zygote. Signup and view all the answers

Study Notes

Water and its Importance

All living organisms require water; cells consist of 70-95% water.
Survival without food can last weeks, but only about one week without water.
Approximately 75% of Earth's surface is covered in water, contributing to its habitability.
Water has two polar covalent bonds, facilitating hydrogen bond formation.

Emergent Properties of Water

Cohesion: Attraction between like molecules; responsible for surface tension.
Adhesion: Attraction between different kinds of molecules; plays a role in transpiration.
Temperature Moderation: Water's high specific heat allows it to absorb and retain heat.
Heat of Vaporization: High heat required to convert liquid water to gas; prevents overheating.
Evaporative Cooling: Surface cooling during evaporation, exemplified by sweating.
Density of Ice: Ice, with a crystalline structure, is less dense than liquid water, allowing it to float.
Solvent Properties: Water dissolves polar molecules, making it a good solvent.

Carbon and Organic Chemistry

Carbon is essential for life, forming the backbone of biomolecules with capacity for four covalent bonds.
Organic Chemistry: The study of carbon-containing molecules, ranging from simple (methane) to complex (proteins).
Organic vs Inorganic: Organic compounds contain carbon covalently bonded (CHON), whereas inorganic lacks C-C or C-H bonds.

Hydrocarbons and Isomers

Hydrocarbons consist of only hydrogen and carbon, varying by length, double bond position, branching, and rings.
Isomers: Compounds with the same molecular formula but different structures, including:
- Structural Isomers: Different connectivity.
- Cis-Trans Isomers: Different arrangements around double bonds (cis: same side, trans: opposite sides).
- Enantiomers: Mirror images that are non-superimposable, typically involving a carbon attached to four different groups.

History of Organic Matter Exploration

Vitalism: The belief in a vital force unique to living organisms was debunked in the 1800s.
Friedrich Wohler synthesized urea from inorganic compounds in the 1820s.
The Miller Experiment in the 1950s demonstrated the chemical origins of life with the spontaneous formation of amino acids.

Plant Evolution

Plant evolution follows this path: photosynthetic protists → algae → lower plants.
Vascular plants contain structured systems (xylem & phloem) for nutrient and water transport.

Genetics Overview

Haploid (1n): One set of chromosomes; Diploid (2n): Two sets of chromosomes.
Mitosis: Asexual reproduction, producing two identical daughter cells; can be haploid or diploid.
Meiosis: Prepares for sexual reproduction, leading to four non-identical haploid daughter cells.

Plant Genetics Structure

Gametophyte: Haploid plant phase generating gametes (sperm & eggs).
- Archegonium: Female structure producing eggs.
- Antheridium: Male structure producing sperm.
Sporophyte: Diploid phase producing spores through meiosis.

Cell Structure and Types

Cell Theory: Fundamental properties - all living things are made of cells, cells are the basic units of life, and cells arise from other cells.
Prokaryotic Cells: Generally smaller, simpler cells without a nucleus (e.g., bacteria and archaea).
Eukaryotic Cells: Larger, complex cells with membrane-bound organelles, including plants, animals, and fungi.

Cellular Organelles and Functions

Nucleus: Contains DNA and is membrane-bound.
Ribosomes: Synthesize proteins; found in both cell types.
Endoplasmic Reticulum: Modifies proteins and synthesizes lipids; can be rough (with ribosomes) or smooth (without).
Golgi Apparatus: Sorts and distributes proteins and lipids.
Vesicles: Transport materials around the cell.

Nucleic Acids and Protein Synthesis

Nucleotides: Comprised of phosphate, sugar, and nitrogenous base (A, T, C, G).
DNA Directionality: Runs from 5' to 3'; nucleotide structure is crucial for replication and expression.
DNA Extraction: Involves breaking cells, clearing debris, and isolating DNA through precipitative methods.

Macromolecules Overview

Carbohydrates: Provide energy (sugars) and structure (cellulose).
Proteins: Composed of 20 amino acids; complex structures with specific functions.
Lipids: Diverse structures (e.g., fats, steroids) that repel water and form membranes.
Nucleic Acids: Store genetic information and drive protein synthesis.

Enzymes and Their Functions

Enzymes lower activation energy, boosting reaction rates; they are not consumed in reactions.
Factors like heat and pH can denature proteins, altering their functional structure.

Summary of Plant Life Cycle

Alternation of Generations: The cycle between gametophyte (haploid) and sporophyte (diploid) phases defines plant reproduction.
This method supports genetic diversity and adaptation in plant species.

Studying That Suits You

Use AI to generate personalized quizzes and flashcards to suit your learning preferences.

Description

Explore the vital role of water in living organisms and its unique properties. This quiz covers water's composition, its importance for survival, and the emergent properties such as cohesion and adhesion. Understand why water is essential for life on Earth.