Biology Test 2 Vocab

Character

Detectable inheritable feature
e.g. flower colour

Trait

Character determined by an allele
e.g. purple or white flower

Dominant trait

Trait that only requires one copy the gene to express itself (capital letters)
e.g. brown eyes

Recessive trait

Trait that requires both copies of the gene to express itself (lower case letters)
e.g. blue eyes

True breeding

Fertilization that produces offsprings with the same traits

Allele

Alternate form of a gene. Responsible for variations in the inherited characters

Locus

Location of a gene

Phenotype

Physical expression of a gene

Genotype

Organism's genetic makeup

Homozygous

Having two identical alleles of a gene (BB or bb)

Heterozygous

Having two different alleles for a gene

Punnett square

Table showing all possible combinations of alleles.

Test crossing

Test done to determine if an organism expressing the dominant phenotype is homozygous or heterozygous

Monohybrid cross

Cross of heterozygous F1s with their parents differering in only one gene

Dihybrid cross

Cross of heterozygous F1s with their parents differing in two genes

Incomplete dominance

Heterozygotes show an intermediate phenotype
e.g. red pink white flower

Codominance

Heterozygotes express both alleles
e.g. AB blood type

Multiple alleles

More than two possible alleles for a gene
e.g. Iᴬ, Iᴮ, i blood genotypes

Pleiotropy

A single gene has multiple phenotypic effects
e.g. sickle cell anemia

Epistasis

Gene at one locus alters the phenotypic expression of a gene at another locus
e.g. black brown blond dog

Polygenic inheritance

Two or more genes leads to a single phenotypic character
e.g. skin color

Autosomal recessive disorder

Phenotype that is expressed by two recessive alleles found on an autosome

Autosomal dominant disorder

Phenotype that is expressed by only one disease allele on an autosome

X-linked trait

Phenotype that is expressed by recessive alleles in the X chromosome

Lyon hypothesis

X-Inactivation occurs randomly in embryonic cells

Pedigree

Diagram showing the occurrence of a genetic trait in several generations of a family.

Fimbriae

Appendage to attach to host and gain entrance

Sex pili

Structure for bacterial conjugation

Photoautotroph

Organism that uses light as a source of energy to synthesize organic substances.

Chemoautotroph

Organism that produces energy by oxidation of inorganic compounds

Chemoheterotroph

Organism that consumes organic molecules for energy and ATP

Saprophytic

Organism that absorb nutrients from dead organisms

Symbiosis

Interaction between smaller symbiont and larger host

Obligate aerobe

Bacteria that require oxygen to grow

Facultative anaerobe

Bacteria that grows with or without oxygen (is capable of fermentation)

Obligate anaerobe

Organism that cannot grow in the presence of oxygen

Colonial

Collection of unicellular organisms living together

Charophyte

Group of green algae most closely related to land plants

Volvox

Colonial chlorophyta algae exhibiting division of labour between cells

Chlamydomonas

Unicellular chlorophyta algae with two flagella

Phragmoplast

A group of microtubules

Rhizoid

Primitive roots of the moss

Stomata

Pores for gas exchange

Waxy cuticle

Very waxy (lipid) material which prevents leaves from drying out in the sun

Desiccation

Drying out of a living organism

Vascular system

Composed of the xylem and the phloem

Xylem

Nonliving vascular tissue that carries water and dissolved minerals up using passive transport

Phloem

Living vascular tissue that carries sugar and organic substances up and down using active transport

Lignin

Complexe polysaccharide which enables plants to have support and grow tall

H2O fertilization

The sperm needs water to meet the female gamete

Pollen

Male sperm in plants

Seed

Fertilized egg (zygote) in a protective coat which provides nutrition and protection