Genetics and DNA: Key Concepts for Biology Students

A comprehensive vocabulary flashcard set covering key concepts in genetics, DNA, cellular division, inheritance, biotechnology, and evolution for biology students.

chromosome

a tightly coiled strand of DNA

deoxyribonucleic acid (DNA)

the carrier of genetic information; located in the nucleus of a cell

double helix

the structure of a DNA molecule; a double-stranded spiral

gene

a segment of DNA, the basic functional unit of heredity

genome

an organism's entire sequence of DNA

genotype

the genetic code for an organism

heredity

the passing on of traits from parents to their offspring

nucleotide

the building block of DNA, consisting of a sugar, a phosphate and a nitrogenous base (adenine, guanine, thymine or cytosine)

phenotype

how the genotype is physically expressed

plasmid

a small circular DNA molecule in bacteria and some other microscopic organisms

amino acid

an organic molecule that is the building block of a protein

enzyme

a protein that increases the rate of a specific chemical reaction in the body

nitrogenous

containing nitrogen

proteins

long polymer chains made up of amino acid monomers

ribonucleic acid (RNA)

a nucleic acid similar to DNA that helps to produce proteins from the genes of DNA

transcription

the process in which a cell makes an RNA copy of a piece of DNA

nuclein

a name given to DNA when it was first discovered

asexual reproduction

reproduction in which a single parent produces a genetically identical offspring

binary fission

cell division in single-celled organisms that produces offspring identical to the parent

cell cycle

the process a cell goes through every time it divides

clone

a gene or an organism that is genetically identical to its parent

crossing over

the exchange of genes by homologous chromosomes

diploid

has two sets of chromosomes

gamete

a sex cell - an ova or a sperm

haploid

has a single set of chromosomes

homologous

chromosomes that have the same genes in the same order

meiosis

complex cell division that produces unique haploid gamete cells

mitosis

simple cell division that produces identical cells

sexual reproduction

reproduction in which gametes from two parents fuse to produce a genetically unique offspring

menstruation

monthly discharge of blood and tissue from the lining of the uterus

ovum

a female sex cell, also known as an egg cell (plural ova)

semen

protective fluid that contains sperm

sperm

a male sex cell

allele

a variation of a gene

environmental factor

something in the environment that affects gene expression

expression

the process of converting the instructions in DNA into a trait, such as a protein

monogenic

influenced by a single gene

polygenic

influenced by two or more genes

chromosomal mutation

a mutation caused by a change to a large section of a chromosome

genetic diversity

the range of genes present within a population or species

karyotype

a picture of an organism's full set of chromosomes

mutation

an error in DNA that changes the DNA sequence, which can be caused by DNA replication, or cell division

point mutation

a mutation caused by a change to a single nucleotide base

dominant allele

an allele that only requires one copy to be seen in a phenotype

heterozygous

a genotype of two different alleles

homozygous

a genotype of two of the same allele

recessive allele

an allele that requires two copies to be seen in a phenotype

pedigree chart

a chart that shows the inheritance of a trait through generations of a family

Punnett square

a diagram that shows the possible genotypes of offspring

biotechnology

using living organisms to develop products

recombinant DNA

DNA that has been formed by inserting or combining genes from different organisms

transgenic organism

a living thing that contains recombinant DNA

economic consideration

a factor that takes into account the costs to individuals and groups

ethical consideration

a factor that takes into account what is right and what is wrong

social consideration

a factor that affects society and the people within society

abiotic

non-living

isolation

when a population is cut off from others

natural selection

the process in which organisms that are better suited to their environment tend to survive and reproduce, passing their traits on to further generations

population

a group of organisms of the same species that live and interact within the same area

selection pressure

a factor that can influence which traits are beneficial to the survival of organisms

variation

the difference between individuals in a species, in both genetics and phenotypes

absolute dating

determining the age range of an object, such as a fossil, in numbers of years

biogeography

the study of the past and present distribution of living organisms

common ancestor

an ancestor that is shared by two or more independent species

comparative anatomy

the study of similar anatomical structures in different species in order to understand their evolution

comparative embryology

the study of the similarity of the embryos of different species as they develop

evolution

the way in which organisms change over generations as a result of adaptations that suit their environment

fossil

the geologically altered remains of a previously living organism

fossil record

a record of all fossils that are on Earth

homologous structures

features in different organisms that are similar in structure, but different in function

relative dating

arranging geological objects and rocks in a sequence from oldest to youngest

vestigial structure

a feature of an organism that has lost some or all of its function through evolution

Gondwanaland

the supercontinent that broke from Pangaea approximately 250 million years ago and was made up of the modern-day continents of Africa, South America, Australia and Antarctica

megapode

a class of flightless birds that had large legs and feet and built nesting mounds in which to lay its eggs

theory of evolution by natural selection

a theory that says species have evolved adaptations over time that helped them to survive in their environment

genetic technology

a technology used by scientists to study or alter living things

stem cell

an undifferentiated cell