Practical #3 Flashcards
(95 cards)
Character
A heritable feature of an organism that varies among individuals, features such as flower color in Mendel’s peas or freckles in humans
Trait
A variety or state of a character, such as a white flower color in peas or no freckles on a human.
Structural gene
The functional unit of heredity.
- It is found at particular locations on the chromosome, and the nucleotide sequence determines the primary structure of all
polypeptides and proteins.
Allele
An alternative form of a gene that occurs at the same location on homologous chromosomes.
- For example, the gene that codes for the ABO blood type has three alleles, A, B,
and O
Dominant allele
The allele expressed in a phenotype when a genotype is heterozygous.
- For example, in human blood groups the A and B alleles are dominant to the O allele. A
Recessive allele
The allele not expressed in the phenotype when the genotype is
heterozygous. Recessive alleles are only expressed when the genotype is homozygous.
Homozygous
A genotype with the same alleles for a gene on homologous chromosomes.
Heterozygous:
A genotype with different alleles for a gene on homologous chromosomes.
Genotype
The actual alleles present for a given gene on homologous chromosomes.
- Genotypes are expressed in letters.
Phenotype
The outward expression of a genotype, or what the trait looks like externally, or physically.
- Phenotypes are as described adjective words.
Codominant
A genetic condition that occurs when neither allele is dominant over another, but both are expressed in the phenotype
- For example, AB blood types
Internal fertilization
occurs when the sperm is transferred directly to the female’s body, and the secondary oocytes are fertilized inside of the female.
- The anatomy of the male is designed for the direct transfer of sperm to the female’s body
Viviparity
is when the embryos are retained in the female’s body.
What are the three parts of sperm?
the head, mid piece, and tail.
The head of the sperm contains what?
It contains the nucleus and is tipped with the acrosome.
What is the acrosome?
is composed of granular enzymes to dissolve the zona pellucida, which surrounds the secondary oocyte.
What does the midpiece of sperm contain?
It contains mitochondria for energy production.
What is the tail of sperm?
is a flagellum that propels the sperm cell.
Penis contains what?
erectile tissues.
Erectile tissues
tissues engorge with blood
during an erection.
What are the erectile tissues in the penis?
two corpora cavernosa and corpora spongiosum
Corpora cavernosa location
extends along the length of the penis and are located dorsally to the urethra. This tissue makes up
the bulk of the penis.
Corpora spongiosum location
extends along the length of the penis and is located beneath the corpora cavernosa. It encircles the urethra.
Testes contain what?
lobules