Spring Semester Review - Honors Biology Vocabulary

Flashcards covering key vocabulary from Honors Biology, focusing on Units 5-9 including Photosynthesis, Cellular Reproduction, Patterns of Heredity, Molecular Inheritance, and Biological Evolution.

Biotic Factor

A living component of an ecosystem.

Abiotic Factor

A non-living component of an ecosystem.

Keystone Species

A species that plays a critical role in maintaining the structure of an ecological community and whose impact on the community is disproportionately large relative to its abundance.

Competition

An interaction between organisms or species in which both are harmed when they both require a limited resource, such as food, water, or territory.

Predation

An interaction in which one organism (the predator) kills and consumes another organism (the prey).

Symbiosis

Any type of close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasitic.

Food Chain

A linear sequence of organisms through which nutrients and energy pass as one organism eats another.

Food Web

A network of interconnected food chains depicting the flow of energy and nutrients within an ecosystem.

Producer

An autotrophic organism that produces complex organic compounds from simple inorganic molecules using energy from light (photosynthesis) or chemical reactions (chemosynthesis).

Carnivore

An animal that feeds primarily or exclusively on other animals.

Omnivore

An animal that eats both plants and animals.

Scavenger

An animal that feeds on dead or decaying organic matter.

Herbivore

An animal that feeds primarily on plants.

Primary Consumer

An organism that consumes producers (plants or other photosynthetic organisms).

Secondary Consumer

An organism that consumes primary consumers.

Tertiary Consumer

An organism that consumes secondary consumers.

Carbohydrates

Organic compounds composed of carbon, hydrogen, and oxygen, serving as a primary source of energy for living organisms.

Monomer (Carbohydrates)

Monosaccharides, the simple sugars that are the building blocks of carbohydrates.

ATP (Adenosine Triphosphate)

The primary energy carrier in cells, used to power cellular activities.

Photosynthesis

The process by which green plants and some other organisms use sunlight to synthesize foods from carbon dioxide and water.

Chloroplast

The organelle in plant cells where photosynthesis takes place.

Grana/Granum

Stacks of thylakoids within a chloroplast.

Stroma

The fluid-filled space surrounding the thylakoids inside a chloroplast.

Thylakoid

A membrane-bound compartment inside chloroplasts where the light-dependent reactions of photosynthesis take place.

Light Reaction

The first stage of photosynthesis, in which light energy is converted into chemical energy in the form of ATP and NADPH.

Dark Reaction (Calvin Cycle)

The second stage of photosynthesis, in which carbon dioxide is fixed and converted into glucose using ATP and NADPH.

Chlorophyll

A pigment in plants that absorbs light energy for photosynthesis.

NADP+

An electron carrier involved in photosynthesis.

NADPH

A reduced form of NADP+, carrying high-energy electrons.

Calvin Cycle

The cycle of chemical reactions that fix carbon dioxide to produce three-carbon sugars.

Rubisco

An enzyme present in plant chloroplasts, involved in fixing atmospheric carbon dioxide during photosynthesis and in oxygenation of ribulose-1,5-bisphosphate.

Cell Specialization

The process by which cells differentiate and acquire specific structures and functions.

Asexual Reproduction

A type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring are genetically identical to the parent organism.

Sexual Reproduction

A type of reproduction that involves the fusion of gametes, resulting in offspring with genetic variation from the parents.

Mitosis

A type of cell division that results in two daughter cells each having the same number and kind of chromosomes as the parent nucleus, typical of ordinary tissue growth.

Interphase

The period of the cell cycle during which the cell grows and duplicates its DNA before undergoing mitosis or meiosis.

Chromosome

A thread-like structure of nucleic acids and protein found in the nucleus of most living cells, carrying genetic information in the form of genes.

Centromere

The region of a chromosome to which the microtubules of the spindle attach, via the kinetochore, during cell division.

Sister Chromatid

Two identical copies of a single replicated chromosome that are connected by a centromere.

Chromatin

The material of which chromosomes are made, consisting of DNA and protein.

Homologous Chromosome

A pair of chromosomes having the same gene sequences, each derived from one parent.

Haploid Cell

A cell that has a single set of unpaired chromosomes.

Diploid Cell

A cell that contains two complete sets of chromosomes, one from each parent.

Crossing Over

The exchange of genetic material between homologous chromosomes during meiosis, resulting in recombinant chromosomes.

Meiosis

A type of cell division that results in four daughter cells each with half the number of chromosomes of the parent cell, as in the production of gametes and plant spores.

Gene

A unit of heredity that is transferred from a parent to offspring and is held to determine some characteristic of the offspring.

Allele

One of two or more alternative forms of a gene that arise by mutation and are found at the same place on a chromosome.

Homozygous

Having two identical alleles of a particular gene.

Heterozygous

Having two different alleles of a particular gene.

Dominant

An allele that produces the same phenotype whether inherited with an identical allele copy or with two different alleles.

Recessive

An allele that produces its characteristic phenotype only when its paired allele is identical.

Genotype

The genetic constitution of an individual organism.

Phenotype

The set of observable characteristics of an individual resulting from the interaction of its genotype with the environment.

Incomplete Dominance

A form of inheritance in which one allele for a specific trait is not completely dominant over the other allele, resulting in a blended phenotype.

Codominance

A form of inheritance in which both alleles for a gene are fully expressed, resulting in offspring with a phenotype that is neither dominant nor recessive.

Multiple Alleles

A type of non-Mendelian inheritance pattern that involves more than just the typical two alleles that usually code for a certain trait in a species.

Polygenic Traits

Traits that are influenced by multiple genes rather than just one.

Sex-Linked Genes

Genes located on the sex chromosomes.

Pedigree

A diagram that shows the occurrence and appearance of phenotypes of a particular gene or organism and its ancestors from one generation to the next.

Chargaff's Rules

States that DNA from any cell of all organisms should have a 1:1 ratio (base Pair Rule) of pyrimidine and purine bases and, more specifically, that the amount of guanine is equal to cytosine and the amount of adenine is equal to thymine.

DNA

A molecule that carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses.

Monomer (DNA)

Nucleotides, each composed of a deoxyribose sugar, a phosphate group, and a nitrogenous base.

Nitrogenous Bases

Adenine (A), guanine (G), cytosine (C), and thymine (T) in DNA; adenine (A), guanine (G), cytosine (C), and uracil (U) in RNA.

Purine

A nitrogenous base that has a two-ring structure; either adenine or guanine.

Pyrimidine

A nitrogenous base that has a one-ring structure; either cytosine, thymine, or uracil.

Antiparallel

Running parallel but moving or oriented in opposite directions.

DNA Replication

The biological process of producing two identical replicas of DNA from one original DNA molecule.

Leading Strand

A single DNA strand that, during DNA replication, is replicated in the 5' – 3' direction, in a continuous fashion.

Lagging Strand

A strand of the DNA double helix that is oriented in the 5' to 3' direction, away from the replication fork. Because of its orientation, replication of the lagging strand is more complex than that of the leading strand.

Okazaki Fragments

Short sequences of DNA nucleotides which are synthesized discontinuously and later linked together by the enzyme DNA ligase to create the lagging strand during DNA replication.

DNA Helicase

An enzyme that unwinds the DNA double helix during replication.

DNA Polymerase

An enzyme that synthesizes new DNA strands by adding nucleotides to the 3' end of a growing strand.

DNA Ligase

An enzyme that joins DNA fragments together by forming phosphodiester bonds.

DNA Primase

An enzyme that synthesizes short RNA primers to initiate DNA replication.

PCR (Polymerase Chain Reaction)

A technique used to amplify specific DNA sequences, making numerous copies of the DNA segment.

Gel Electrophoresis

A laboratory method used to separate mixtures of DNA, RNA, or proteins according to their size and electrical charge.

RNA

A nucleic acid present in all living cells. Its principal role is to act as a messenger carrying instructions from DNA for controlling the synthesis of proteins

Transcription

The process by which the information in a strand of DNA is copied into a new molecule of messenger RNA (mRNA).

Translation

The process in which ribosomes in a cell's cytoplasm create proteins, following transcription of DNA to RNA in the cell's nucleus.

Codon

A sequence of three nucleotides that together form a unit of genetic code in a DNA or RNA molecule.

Anticodon

A sequence of three nucleotides forming a unit of genetic code in a transfer RNA molecule, corresponding to a complementary codon in messenger RNA.

mRNA (messenger RNA)

A molecule of RNA encoding a chemical 'blueprint' for a protein product.

tRNA (transfer RNA)

An adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length, that serves as the physical link between the mRNA and the amino acid sequence of proteins.

RNA Polymerase

An enzyme that is responsible for making RNA from a DNA template.

Ribosomes

A structure upon which proteins are assembled.

Mutation

A change in the DNA sequence of an organism.

Point Mutation

A mutation affecting only one or very few nucleotides in a gene sequence.

Chromosomal Mutation

Any change in the structure or number of chromosomes.

Frameshift Mutation

A genetic mutation caused by indels (insertions or deletions) of a number of nucleotides in a DNA sequence that is not divisible by three.

Evolution

Change in the heritable characteristics of biological populations over successive generations.

Species

A group of living organisms consisting of similar individuals capable of exchanging genes or interbreeding.

Natural Selection

The differential survival and reproduction of individuals due to differences in phenotype.

Genetic Drift

Variation in the relative frequency of different genotypes in a small population, owing to the chance disappearance of particular genes as individuals die or do not reproduce.

Gene Flow

The transfer of genetic variation from one population to another.

Homologous Structures

Structures in different species that are similar because of common ancestry.

Convergent Evolution

The process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches.

Speciation

The evolutionary process by which populations evolve to become distinct species.

Cladogram

A branching diagram showing the cladistic relationship between a number of species.