Honors Biology Spring Semester Review Flashcards

Flashcards covering Unit 5 (Photosynthesis), Unit 6 (Cellular Reproduction), Unit 7 (Patterns of Heredity - Genetics), Unit 8 (Molecular Inheritance - DNA), and Unit 9 (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 is disproportionately large relative to its abundance.

Competition

An interaction in which organisms or species compete for a resource that is in limited supply.

Predation

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

Symbiosis

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

Mutualism

A type of symbiosis in which both species benefit.

Commensalism

A type of symbiosis in which one species benefits and the other is not harmed or helped.

Parasitism

A type of symbiosis in which one species benefits (the parasite) and the other is harmed (the host).

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, representing the complex feeding relationships within a community.

Producer

An autotrophic organism that produces its own food through photosynthesis or chemosynthesis.

Carnivore

An animal that eats 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 eats only plants.

Primary Consumer

An organism that eats producers.

Secondary Consumer

An organism that eats primary consumers.

Tertiary Consumer

An organism that eats secondary consumers.

Carbohydrates

Organic compounds containing carbon, hydrogen, and oxygen, often with a hydrogen-oxygen atom ratio of 2:1; often used for energy storage.

Monomer

A molecule that can be bonded to other identical molecules to form a polymer.

Monosaccharides

Simple sugars, such as glucose and fructose.

Disaccharides

Sugars composed of two monosaccharides linked together, such as sucrose and lactose.

Polysaccharides

Complex carbohydrates composed of many monosaccharides linked together, such as starch, cellulose, and glycogen.

ATP

Adenosine triphosphate; the primary energy currency of the cell.

Photosynthesis

The process used by plants and other organisms to convert light energy into chemical energy that can be later released to fuel the organisms' activities.

Chloroplast

Organelle found in plant cells and eukaryotic algae that conducts photosynthesis.

Grana/Granum

Stacks of thylakoids inside chloroplasts where the light-dependent reactions of photosynthesis occur.

Stroma

The fluid-filled space surrounding the grana inside a chloroplast where the Calvin cycle (light-independent reactions) takes place.

Thylakoid

A membrane-bound compartment inside chloroplasts and cyanobacteria 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 converted into glucose using the ATP and NADPH produced in the light reaction.

Chlorophyll

A green pigment found in plants and algae that absorbs light energy for photosynthesis.

NADP+

Nicotinamide adenine dinucleotide phosphate; an electron carrier involved in the light reactions of photosynthesis.

NADPH

The reduced form of NADP+; a reducing agent used in the Calvin cycle to convert carbon dioxide into glucose.

Calvin Cycle

The cycle of chemical reactions that occur in the stroma of the chloroplast during photosynthesis.

Rubisco

An enzyme involved in the first major step of carbon fixation, a process by which atmospheric carbon dioxide is converted by plants and other photosynthetic organisms to energy-rich molecules such as glucose.

Cellular Respiration

The metabolic process that occurs in cells to break down glucose and produce ATP.

Cell Specialization

The process by which cells become specialized in their structure and function.

Asexual Reproduction

A type of reproduction that does not involve the fusion of gametes or change in the number of chromosomes. The offspring inherit the full set of genes of their single parent.

Sexual Reproduction

A type of reproduction that involves the fusion of gametes and results in offspring with a combination of genetic material from two 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 resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.

Cell Cycle Checkpoints

Control mechanisms in eukaryotic cells which ensure proper cell division.

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 chromosome that are connected by a centromere.

Chromatin

The material of which the chromosomes of organisms other than bacteria (i.e., eukaryotes) are composed. It consists of protein, RNA, and DNA.

Homologous Chromosomes

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 sets of chromosomes.

Crossing Over

The exchange of genes between homologous chromosomes, resulting in a mixture of parental characteristics in offspring.

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.

Genetics

The study of heredity and the variation of inherited characteristics.

Gregor Mendel

Known as the 'father of modern genetics' for his studies on inheritance in pea plants.

Principle of Dominance

States that some alleles are dominant and others are recessive. An organism with at least one dominant allele will display the effect of the dominant allele.

Law of Segregation

States that allele pairs separate or segregate during gamete formation, and randomly unite at fertilization.

Law of Independent Assortment

States that genes for different traits assort independently of one another during gamete formation.

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 or with a different allele.

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 Inheritance

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

Codominance

A relationship between two versions of a gene. Individuals receive one version of a gene, called an allele, from each parent. If the alleles are different, usually one allele will be expressed, while the other allele is silenced. But in codominance, neither allele is recessive and the phenotypes of both alleles are expressed.

Multiple Alleles

Three or more possible alleles determine the phenotype for a trait.

Polygenic Traits

Traits that are controlled by multiple genes (height, skin color etc.).

Sex-Linked Genes

A gene located on a sex chromosome.

Carrier

An individual or other organism that has inherited a recessive allele for a genetic trait or mutation but does not display that trait or show symptoms of the disease.

Pedigree

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

Chargaff

Known for discovering that in DNA the number of guanine units is equal to the number of cytosine units and the number of adenine units is equal to the number of thymine units.

Franklin

Performed X-ray diffraction studies of DNA that were crucial in determining its structure.

Pauling

Made important contributions to numerous fields, including the determination of protein structures.

Watson & Crick

Famous for determining the double-helical structure of DNA.

Nitrogenous Base

A nitrogen-containing molecule that has the same chemical behavior as a base. The four nitrogenous bases found in DNA are adenine (A), guanine (G), cytosine (C), and thymine (T).

Purine

A heterocyclic aromatic organic compound that consists of two rings, a pyrimidine ring fused to an imidazole ring. The purines found in DNA are adenine (A) and guanine (G).

Pyrimidine

A heterocyclic aromatic organic compound that consists of a single ring. The pyrimidines found in DNA are cytosine (C) and thymine (T).

Antiparallel

Refers to the arrangement of the two strands of DNA in a double helix, which run in opposite directions.

DNA Replication

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

Semi-Conservative Replication

Method by which DNA replicates, in which each original strand acts as a template for a new strand.

Leading Strand

The strand of DNA that is continuously synthesized during replication.

Lagging Strand

A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork.

Okazaki Fragments

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

DNA Helicase

An enzyme that unwinds the DNA double helix during replication.

DNA Polymerase

An enzyme that synthesizes new DNA strands during replication.

DNA Ligase

An enzyme that joins Okazaki fragments together to form a continuous DNA strand.

DNA Primase

A type of RNA polymerase that creates a short RNA sequence, called a primer, onto a single-stranded DNA template.

Polymerase Chain Reaction (PCR)

A laboratory technique used to amplify a single copy or a few copies of a segment of DNA across several orders of magnitude, generating thousands to millions of copies of a particular DNA sequence.

Gel Electrophoresis

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

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 by which a sequence of nucleotide triplets in a messenger RNA (mRNA) molecule gives rise to a specific sequence of amino acids during synthesis of a protein.

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 (tRNA) molecule, corresponding to a complementary codon in messenger RNA (mRNA).

mRNA

Messenger RNA; molecules carry the coding sequences for protein synthesis and are called transcripts.

tRNA

Transfer RNA; Small RNA molecules that carry amino acids to the ribosome for polymerization.

RNA Polymerase

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

Ribosomes

A complex molecular machine that makes proteins. It is composed of structural and catalytic rRNAs, and many distinct proteins.