Elements of Biology I (BLGY-105)

What are the four major biological molecules?

Carbohydrates, lipids, proteins, nucleic acids.

What are the monomers of proteins?

Amino acids.

What are the monomers of nucleic acids?

Nucleotides.

What is the function of enzymes?

Speed up chemical reactions by lowering activation energy.

What are the two major cell types?

Prokaryotic & eukaryotic.

What organelles are found only in plant cells?

Chloroplasts, central vacuole, cell wall.

What organelle is responsible for ATP production?

Mitochondria.

What organelle is responsible for photosynthesis?

Chloroplast.

What is diffusion?

Movement of molecules from high → low concentration.

What is osmosis?

Diffusion of water across a membrane.

What is active transport?

Requires energy (ATP) to move molecules against gradient.

What is ATP?

Main energy currency of the cell.

What is the equation for photosynthesis?

CO₂ + H₂O + light → glucose + O₂.

Where does photosynthesis occur?

Chloroplast.

What do the light reactions produce?

O₂, ATP, NADPH.

What does the Calvin cycle produce?

Sugar (G3P).

What is the purpose of cellular respiration?

Convert glucose → ATP.

What are the three stages of cellular respiration?

Glycolysis, Krebs cycle, electron transport chain.

Where is most ATP made?

Electron transport chain.

When does fermentation occur?

When no oxygen is available.

What does mitosis produce?

2 identical diploid cells.

What is the purpose of mitosis?

Growth, repair, asexual reproduction.

What is cytokinesis?

Division of cytoplasm.

What does meiosis produce?

4 genetically unique haploid gametes.

What are the sources of genetic variation?

Crossing over, independent assortment, random fertilization.

What is the difference between haploid and diploid?

Haploid = 1 set of chromosomes; diploid = 2 sets.

What is Mendel’s Law of Segregation?

Alleles separate during gamete formation.

What is the difference between dominant and recessive?

Dominant masks recessive.

What is the difference between genotype and phenotype?

Genotype = genes; phenotype = traits.

What is an example of codominance?

AB blood type.

What is the structure of DNA?

Double helix of nucleotides (A-T, C-G).

What is transcription?

DNA → mRNA (in nucleus).

What is translation?

mRNA → protein (at ribosome).

What is a mutation?

Change in DNA sequence.

What does PCR do?

Amplifies DNA.

What is gel electrophoresis?

Separates DNA fragments by size.

What is a GMO?

Organism with inserted foreign DNA.

What is evolution?

Change in allele frequencies over time.

What is natural selection?

Individuals with advantageous traits reproduce more.

What is genetic drift?

Random change in allele frequencies (small populations).

What is gene flow?

Movement of alleles between populations.

What is the biological species concept?

Can interbreed & produce fertile offspring.

What is allopatric speciation?

Geographic isolation.

What is sympatric speciation?

No geographic barrier.

What are reproductive barriers?

Prezygotic & postzygotic.

What do fossils show?

Change over time.

What are homologous structures?

Same origin, different function.

What are analogous structures?

Same function, different origin.

What is a clade?

Ancestor + all descendants.

What are the three domains of life?

Bacteria, Archaea, Eukarya.

Why are viruses not considered cells?

No membranes, no metabolism, need host to reproduce.

How do prokaryotes reproduce?

Binary fission.

What are the four major plant groups?

Bryophytes, ferns, gymnosperms, angiosperms.

How do fungi obtain nutrients?

By absorption.

What are the characteristics of animals?

Multicellular, heterotrophic, eukaryotic.

What are key traits of animals?

No cell walls, nervous & muscle tissue.

What is the correct sequence of events during transcription?

Initiation, elongation, termination.

What does the backbone of DNA consist of?

A repeating sugar‑phosphate‑sugar‑phosphate pattern.

What is the enzyme responsible for RNA synthesis?

RNA polymerase.

How many nucleotides are in a codon?

3.

Translation converts the information in ___ to ___.

RNA; a protein.

DNA and RNA are polymers made of _______ monomers.

Nucleotide.

What causes Mad Cow Disease?

Infectious proteins called prions.

What is transcription?

Manufacture of a strand of RNA complementary to a strand of DNA.

In a DNA double helix, adenine pairs with _______ and guanine pairs with _______.

Thymine; cytosine.

After replication, _______.

Each new DNA double helix consists of one old strand and one new strand.

What is the process by which genotype becomes expressed as phenotype?

Gene expression.

Bacterial RNA polymerase binds to the:

Promoter.

What proteins bind to silencers to prevent gene expression?

Repressors.

How do cells communicate with one another?

Via signal transduction pathways.

What is a gene that causes cancer called?

Oncogene.

What is the best definition for recombinant DNA?

DNA that includes nucleotides from two different sources.

What is the definition of a transgenic organism?

An organism containing a gene from another species.

Gel electrophoresis separates DNA fragments based on:

Length.

What field studies complete sets of genes?

Genomics.

What was the goal of the Human Genome Project?

To determine the nucleotide sequence of all of the DNA in the human genome.

Which characteristic indicates a population at Hardy-Weinberg equilibrium?

The population is not evolving.

Natural selection can be defined as:

A process where organisms with certain inherited traits are more likely to survive and reproduce.

What is the total collection of alleles in a population called?

Gene pool.

In the Hardy-Weinberg formula, what does p² represent?

Frequency of the homozygotes for one allele (usually the dominant homozygote, AA).

Which group of organisms can be considered a population?

The termites infesting your house (excluding microorganisms in their guts).

What statement about the voyage of the Beagle is TRUE?

It became a tremendous opportunity for Darwin to collect fossils, plants, and animals.

What is the current geological era?

Cenozoic.

Biological species consist of groups of:

Populations.

The wing of a penguin is _______ the wing of a butterfly.

Analogous to.

Which taxonomic level is most inclusive?

Order.

What follows a period of mass extinction?

Explosive diversification.

What are bony fins used to 'walk' when water dries out an example of?

An exaptation.

What is the science of naming, identifying, and classifying organisms called?

Taxonomy.

What is a reproductive barrier preventing interbreeding between closely related species?

Prezygotic barrier.

What defines a clade?

An ancestral species and all its evolutionary descendants.

What does plate tectonics NOT cause?

Sympatric speciation.