Biology Exam Preparation Flashcards

These flashcards cover key concepts and vocabulary from biology including properties of life, biological molecules, metabolism, cell structure, and genetics, designed for exam preparation.

What distinguishes living things from non-living things?

Characteristics such as cellular structure, reproduction, metabolism, growth, and response to stimuli.

Define atomic number and mass number.

Atomic number is the number of protons in an atom's nucleus, while mass number is the total number of protons and neutrons.

What is an isotope?

Atoms of the same element that have the same number of protons but different numbers of neutrons.

What is a covalent bond?

A bond formed when two atoms share one or more pairs of electrons.

What is an acid?

A substance that increases the concentration of hydrogen ions (H+) in a solution.

Explain dehydration synthesis.

A reaction that builds larger molecules from smaller ones by removing water.

What is the generalized structure of an amino acid?

An amino group (NH2), a carboxyl group (COOH), a hydrogen atom, and a variable R group.

How do alpha-glycosidic and beta-glycosidic linkages differ?

Alpha-glycosidic linkages connect carbohydrates in a way that allows for energy storage, while beta-glycosidic linkages are found in structural carbohydrates like cellulose.

What is the role of enzymes in hydrolysis?

Enzymes aid in breaking down polymers into monomers through the addition of water.

Define metabolism.

The sum of all chemical reactions that occur within a living organism to maintain life.

What are the laws of thermodynamics?

The first law states energy cannot be created or destroyed; the second law states that energy transfer increases entropy.

What is the function of ATP in cellular reactions?

ATP provides energy for cellular processes through hydrolysis, coupling reactions.

Distinguish between mitosis and meiosis.

Mitosis results in two identical daughter cells, while meiosis results in four genetically diverse gametes.

What is incomplete dominance?

A genetic situation in which neither allele is completely dominant, resulting in a blended phenotype.

Define phenotype and genotype.

Phenotype is the observable traits of an organism, while genotype is the genetic makeup.

What is synapsis in meiosis?

The pairing of homologous chromosomes during prophase I, leading to genetic recombination.

Explain the role of the final electron acceptor in cellular respiration.

The final electron acceptor, usually oxygen, is essential for the electron transport chain to produce ATP efficiently.

What characterizes saturated vs unsaturated fatty acids?

Saturated fatty acids have no double bonds between carbon atoms, while unsaturated fatty acids have one or more double bonds.

What does a karyotype show?

A karyotype displays the number and appearance of chromosomes in a person's cells.

What is a Punnett square?

A diagram used to predict the genetic outcome of a particular cross or breeding experiment.

What is the importance of mutations in evolution?

Mutations can introduce genetic diversity, providing material for natural selection and evolution.

How does active transport differ from passive transport?

Active transport requires energy to move molecules against their concentration gradient, while passive transport does not.

What does it mean for DNA replication to be semiconservative?

Each new DNA molecule consists of one original strand and one newly synthesized strand.

Which of the following describes a key characteristic of living organisms?

A) Inability to adapt to environment, B) Presence of a cellular structure, C) Absence of metabolism, D) Fixed size and shape. Correct: B

An atom has 8 protons, 8 electrons, and 9 neutrons. What is its mass number?

A) 8, B) 9, C) 16, D) 17. Correct: D

A chemical bond formed by the sharing of electrons between two atoms is known as a:

A) Ionic bond, B) Hydrogen bond, C) Covalent bond, D) Metallic bond. Correct: C

According to the second law of thermodynamics, energy transfers always lead to an increase in the universe's:

A) Order, B) Entropy, C) Enthalpy, D) Free energy. Correct: B

If a person has two different alleles for a particular gene, they are considered:

A) Homozygous recessive, B) Homozygous dominant, C) Heterozygous, D) Polygenic. Correct: C

Which type of glycosidic linkage is characteristic of cellulose, providing structural support in plants?

A) Alpha-1,4 glycosidic linkage, B) Beta-1,4 glycosidic linkage, C) Alpha-1,6 glycosidic linkage, D) Beta-1,6 glycosidic linkage. Correct: B

What is an allele?

An alternative form of a gene, often found at the same locus on homologous chromosomes.

What is an enzyme?

A protein that acts as a biological catalyst to speed up specific biochemical reactions without being consumed in the process.

Define homeostasis.

The ability or tendency of an organism or a cell to maintain stable internal conditions suitable for life, despite external fluctuations.

What is a nucleotide?

The basic monomer unit of nucleic acids (DNA and RNA), composed of a five-carbon sugar, a phosphate group, and a nitrogenous base.

Explain the process of transcription.

The process in which the genetic information encoded in a DNA strand is copied into a messenger RNA (mRNA) molecule.

Biology often defines life through a set of universal characteristics. Elaborate on at least five fundamental characteristics that distinguish living organisms from non-living matter. For each characteristic, briefly explain its significance.

Key characteristics of living organisms include:

1. Cellular Structure: All living things are composed of one or more cells, the basic unit of life. Cells carry out all essential life functions.
2. Reproduction: Living organisms produce offspring, either asexually or sexually, ensuring the continuation of their species.
3. Metabolism: Living things carry out various chemical reactions to obtain and use energy, grow, and repair cells. This includes both anabolism (building up) and catabolism (breaking down).
4. Growth and Development: Organisms increase in size and often undergo differentiation over their lifespan according to their genetic blueprint.
5. Response to Stimuli: Living things react to changes in their environment (e.g., light, temperature, touch) to maintain homeostasis or adapt.
6. Homeostasis: Maintenance of a stable internal environment despite external fluctuations.
7. Adaptation/Evolution: Populations of living organisms can evolve over generations, adapting to their environment through natural selection.

Explain the definitions and significance of atomic number and mass number. Furthermore, describe what an isotope is and how isotopes of the same element differ from one another in terms of their subatomic particles and properties.

• Atomic Number (Z): The number of protons in an atom's nucleus. It determines the element's identity and position on the periodic table.
• Mass Number (A): The total number of protons and neutrons in an atom's nucleus. It represents the approximate atomic mass of the atom.
• Isotope: Atoms of the same element that have the same number of protons (same atomic number) but different numbers of neutrons. This difference in neutron count results in different mass numbers for isotopes of the same element. For example, Carbon-12 has 6 protons and 6 neutrons, while Carbon-14 has 6 protons and 8 neutrons. While their chemical properties are generally similar due to the same number of electrons, their physical properties (e.g., mass, stability, radioactivity) can differ considerably.

Compare and contrast covalent bonds and ionic bonds. Describe the fundamental mechanism of electron interaction in each type of bond and provide an example of a molecule or compound that primarily uses each bonding type.

• Covalent Bond:
  • Mechanism: Formed by the sharing of one or more pairs of electrons between two atoms, typically nonmetals with similar electronegativities. The sharing allows both atoms to achieve a stable electron configuration (often a full valence shell).
  • Example: H2O (water), where oxygen shares electrons with two hydrogen atoms. Methane (CH4).
• Ionic Bond:
  • Mechanism: Formed by the complete transfer of one or more electrons from one atom (typically a metal with low electronegativity) to another (typically a nonmetal with high electronegativity). This transfer creates oppositely charged ions (cations and anions), which are then attracted to each other by electrostatic forces.
  • Example: NaCl (sodium chloride), where sodium donates an electron to chlorine, forming Na^+ and Cl^- ions.