Biological Sciences Overview

This set of flashcards covers key concepts in biological sciences, including the scientific method, biological macromolecules, cell structure, and molecular biology processes.

What is the main goal of basic science?

To expand knowledge for its own sake.

What does applied science aim to do?

Use scientific knowledge to solve real-world problems.

What is the first step of the scientific method?

Ask a question.

What comes after making observations in the scientific method?

Form a hypothesis.

List the steps of the scientific method in order.

1. Ask a question 2. Make observations 3. Form a hypothesis 4. Conduct an experiment 5. Analyze data 6. Draw conclusions 7. Communicate results.

What is the smallest unit of biological organization?

Atom.

Name the levels of biological organization from smallest to largest.

Atom, Molecule, Organelle, Cell, Tissue, Organ, Organ System, Organism, Population, Community, Ecosystem, Biosphere.

What does the atomic number represent?

The number of protons in an atom.

How is mass number calculated?

By adding the number of protons and neutrons.

What do acids release and how do they affect pH?

Acids release H⁺ and lower pH.

What is the effect of bases on pH?

They absorb H⁺ or release OH⁻, increasing pH.

What do buffers do in blood?

Keep blood pH around 7.4.

What gives water its properties as an excellent solvent?

Its polarity.

What type of molecules can water dissolve?

Ionic and polar molecules, but not nonpolar ones.

What do hydrocarbons consist of?

Only hydrogen and carbon.

Give examples of organic molecules.

Carbohydrates, lipids, proteins, nucleic acids.

What is hydrolysis?

A process that breaks polymers into monomers using water.

Define dehydration synthesis.

A process that builds polymers by removing water.

List the four types of biological macromolecules.

Carbohydrates, lipids, proteins, nucleic acids.

What is the primary function of carbohydrates?

Energy storage and structure.

What are lipids?

Fats, phospholipids, and steroids.

What are proteins primarily used for?

Enzymes, structure, transport, and signaling.

What is the structure of nucleic acids?

DNA and RNA.

What is glycogen?

Energy storage in animals.

What is starch?

Glucose storage in plants.

What is cellulose?

Plant cell wall structure.

Name the levels of protein structure.

Primary, secondary, tertiary, quaternary.

What does primary protein structure refer to?

Amino acid sequence held together by peptide bonds.

What is the secondary protein structure characterized by?

Alpha-helices and beta-sheets formed by hydrogen bonding.

What defines tertiary protein structure?

The full 3D folding of the protein.

What does quaternary protein structure involve?

Multiple polypeptides together.

How does protein function relate to its structure?

Protein function depends heavily on structure.

What composes the DNA backbone?

Sugar (pentose) and phosphate.

Which bases pair together in DNA?

A pairs with T, G pairs with C.

Where do base pairs face in the structure of DNA?

Inside the double helix.

What do prokaryotic cells lack?

Membrane-bound organelles.

What are the main features of eukaryotic cells?

Compartmentalization with organelles and a nucleus.

List components of the endomembrane system.

ER, Golgi, lysosomes, vesicles, plasma membrane, vacuoles.

What structures are NOT part of the endomembrane system?

Chloroplasts and mitochondria.

What are microfilaments made of?

Actin.

What is the function of microtubules during mitosis?

To pull chromosomes apart.

What do intermediate filaments do?

Anchor the nucleus.

What is the fluid mosaic model?

Model describing the plasma membrane structure as a phospholipid bilayer with proteins.

What increases membrane fluidity?

More unsaturated fatty acids and higher temperatures.

What is osmosis?

Water moving from low solute concentration to high solute concentration.

How does temperature affect diffusion?

Higher temperature leads to faster diffusion.

What is primary active transport?

Transport that uses ATP directly, such as the Na⁺/K⁺ pump.

What is secondary active transport?

Transport that uses energy from one ion moving down its gradient.

Describe exocytosis.

A process used for the secretion of proteins and release of digestive enzymes.

What are internal receptors?

Receptors located in cytoplasm or nucleus that respond to hydrophobic ligands.

What is the role of kinases?

To add phosphate groups.

What are autoinducers?

Bacterial communication signals that activate transcription.

What is the genetic code based on?

3-letter codons.

What does it mean for the genetic code to be degenerate?

There are multiple codons per amino acid.

What is the start codon?

AUG.

How many stop codons are there?

Three.

What is the central dogma of molecular biology?

DNA → RNA → Protein.

When does transcription occur in the process of protein synthesis?

Before translation.

What does RNA polymerase do at the promoter?

It binds the promoter to start transcription.

What are the three sites of the ribosome?

A-site (tRNA entry), P-site (peptide bond formation), E-site (exit site for empty tRNA).

What levels can eukaryotic regulation occur at?

Epigenetic, transcriptional, post-transcriptional, translational, post-translational.

What modifications do histone tails undergo in epigenetics?

Methylation and acetylation.

What effect does acetylation have on gene expression?

It opens chromatin and increases expression.

What is the effect of methylation on gene expression?

It often decreases expression.

What are transcription factors?

Proteins that bind DNA and help initiate transcription.