Bio 101 Midterm

What are the steps of the Scientific Method?

Make an observation, ask a question, form a hypothesis, make a prediction, do an experiment, analyze results.

What is a hypothesis?

A suggested explanation for an event.

What defines reproducibility in scientific research?

What’s true for one researcher should be true for another.

What is a control group?

A group that shows what would happen under normal conditions without any interventions.

What is the difference between an independent and dependent variable?

Independent variable is controlled, while dependent variable is the result of changes in the independent variable.

What is an experimental group?

A group that shows what would happen under abnormal conditions with interventions.

Define osmosis.

The movement of water from an area of high to low concentration across a membrane.

What occurs during diffusion?

Molecules move from an area of high concentration to an area of low concentration to create equilibrium.

What are the traits associated with life?

Growth, reproduction, excretion, evolution, homeostasis, metabolism, DNA, made of cells, movement, heredity, responses to stimuli.

What is the Primordial Soup Hypothesis?

Suggests that life began when complex molecules like ammonia and hydrogen were stimulated to produce amino acids and DNA components.

Explain the Deep Sea Vent Hypothesis.

Proposes that life began in deep sea volcanic vents that produce organic materials from volcanic materials and water.

What are macromolecules?

Large complex molecules essential for various biological functions, including proteins, carbohydrates, lipids, and nucleic acids.

What is the role of enzymes in biological processes?

Proteins that act as catalysts to speed up chemical reactions.

Differentiate between monosaccharides and polysaccharides.

Monosaccharides are simple sugar units, while polysaccharides are complex carbohydrates made from many monosaccharides.

What is the significance of ATP?

Adenosine triphosphate is the primary energy carrier in cells.

Define autotrophs.

Organisms that make their own food using light or chemical energy.

What is cellular respiration?

A process that breaks down glucose and oxygen to produce carbon dioxide, water, and ATP.

What is the function of mitochondria?

To convert sugars into ATP and is known as the powerhouse of the cell.

What occurs during the Krebs Cycle?

ATP and other energy molecules like NADH and FADH2 are produced.

What is the outcome of meiosis?

The production of four haploid cells that differ from the parent cell.

What defines alleles?

Different versions of a gene.

What is codominance?

A genetic scenario where both alleles are fully expressed.

Explain the concept of phenotype plasticity.

The ability to express multiple phenotypes from the same genotype.

What is the relationship between genotype and phenotype?

Genotype refers to the genetic makeup, while phenotype refers to the observable characteristics.

What is the structure of DNA?

A double helix composed of nitrogenous bases: adenine, thymine, guanine, and cytosine.

Define transcription in the context of genetics.

The process of transferring genetic information from DNA to messenger RNA.

What is the basic unit of genetic information?

Gene, which consists of a sequence of nucleotide bases.

What distinguishes prokaryotic cells from eukaryotic cells?

Prokaryotic cells lack a membrane-bound nucleus and organelles, while eukaryotic cells have both.

What is the role of ribosomes in cells?

Ribosomes synthesize proteins by translating messenger RNA.

What is the endosymbiotic theory?

A theory that explains the origin of eukaryotic cells as descendants of symbiotic prokaryotic cells.

Define genetic drift.

The change in the frequency of an allele in a population due to random sampling.

What is the difference between dominant and recessive alleles?

A dominant allele masks the effects of a recessive allele when both are present.

What are the products of the light-dependent reactions in photosynthesis?

ATP and NADPH.

How does the Calvin Cycle utilize ATP and NADPH?

It uses ATP and NADPH to convert carbon dioxide into glucose.

What is the significance of chlorophyll in plants?

Chlorophyll is a pigment that absorbs light energy for photosynthesis.

Describe the structure and function of phospholipids.

Phospholipids form the cell membrane, controlling what enters and leaves the cell.

What are lysosomes and their function?

Organelles that contain enzymes for digesting cellular waste and macromolecules.

Define what is meant by 'cellular homeostasis.'

The process by which biological systems maintain stability while adjusting to conditions that are optimal for survival.

What are steroids and their function?

Steroid hormones that regulate various physiological processes in the body.

What is the function of the Golgi apparatus?

To modify, sort, and package proteins for secretion or use within the cell.

Differentiate between haploid and diploid cells.

Haploid cells have one set of chromosomes; diploid cells have two sets.

What initiates the process of DNA replication?

The unwinding of the DNA double helix by helicase enzymes.

Explain what a substrate is in enzymatic reactions.

The molecule that an enzyme acts upon to facilitate a chemical reaction.

What are some examples of high carbohydrate foods?

Fruits, potatoes, and plants.

What are organelles?

Specialized structures within a cell that perform distinct functions.

What is the role of the cytoskeleton?

It provides structural support and helps in the movement of materials within the cell.

What happens during cytokinesis?

The division of cytoplasm resulting in two separate cells.

Describe the process of natural selection.

The mechanism by which individuals with favorable traits are more likely to reproduce.

What is meant by the term 'phenotype'?

The observable physical characteristics resulting from an organism's genotype.

Explain the purpose of the experimental design in scientific research.

To test a hypothesis by manipulating one variable and measuring its effect.

What essential role do nucleotides play in nucleic acids?

They are the building blocks that make up DNA and RNA.

What is an ecosystem?

A community of living organisms and their interaction with the environment.

Define mutation in genetics.

A change in the DNA sequence that can lead to variation in traits.

What is the importance of photosynthesis to life on earth?

It converts solar energy into chemical energy and produces oxygen.

Identify the primary role of carbohydrates in living organisms.

Main source of energy.

What are the major components of a cell membrane?

Phospholipids, proteins, cholesterol, and carbohydrates.

Define the process of translation in protein synthesis.

The synthesis of proteins from mRNA templates.

What is the main byproduct of cellular respiration?

Carbon dioxide and water.

How do competitive inhibitors affect enzyme activity?

They bind to the active site and prevent substrate from binding,

What distinguishes eukaryotic organisms from prokaryotic organisms?

Eukaryotic organisms have a defined nucleus and membrane-bound organelles, while prokaryotic organisms do not.

What key function do cell membranes serve?

They regulate the movement of substances in and out of the cell.

What effect does temperature have on enzyme activity?

Higher temperatures generally increase reaction rates until denaturation occurs.

Describe the significance of the sodium-potassium pump.

It maintains cell potential by moving sodium out and potassium into the cell.

What is the difference between saturated and unsaturated fats?

Saturated fats have no double bonds between carbon atoms; unsaturated fats have one or more double bonds.

What does homeostasis mean?

The maintenance of stable internal conditions in an organism.

What role do chloroplasts play in plant cells?

They are the site for photosynthesis, converting light energy into chemical energy.

How do enzymes affect the activation energy of a reaction?

Enzymes lower the activation energy required for a reaction to occur.

What do histones do in eukaryotic cells?

They help package DNA into a compact, dense shape.