Flashcards for Biological Basis of Heredity
Topics 2-4:  Cell Reproduction, Recombination, Linkage, and Sex-linked Genes
(29 cards)

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Copyright © 2007-2012 by Dennis O'Neil. All rights reserved.

The general term for the cells in your body that are not directly involved with reproduction. Most cells in multicellular plants and animals are of this type.

somatic cells

The general term for the specialized cells in your body that are created for sexual reproduction. These cells are also called gametes.

sex cells

The cell division process that occurs in somatic cells. One cell divides into two offspring cells that are identical to each other in their chromosome complement. Body tissues such as skin, hair, and muscle, are duplicated by this process.

mitosis

The general term for the cell division process in specialized tissues of ovaries and testes which results in the production of sex cells. This process involves two divisions and results in cells that contain only half the number of chromosomes as somatic cells.

meiosis
A female sex cell or gamete.
ovum (plural ova)

The place in a woman’s reproductive system where sex cells are produced and stored.

ovaries
A male sex cell or gamete.
sperm

The place in a man’s reproductive system where sex cells are produced.

testes

The specific term for the meiosis process in males that produces sperm.

spermatogenesis

The specific term for the meiosis process in females that produces ova.

oögenesis

An immature female sex cell in humans and many other animals produced before birth and stored in the ovaries. These cells complete the meiosis process usually one by one after puberty when hormones trigger ovulation.

oöcyte

The term for the number of chromosomes in a normal somatic cell. This number is 46 (23 pairs) for humans.

diploid number

The term for the number of chromosomes in a normal sex cell. This number is 23 for humans.

haploid number

The kind of cell that is formed when a sperm and an ovum combine their chromosomes at conception. It contains the full complement of chromosomes (in humans 46) and has the potential of developing into an entire organism. This kind of cell is also referred to as a "fertilized" ovum.

zygote

The term for individuals who have parts of both male and female sex organs thereby making their gender somewhat ambiguous.

hermaphrodite

The release of a secondary oöcyte from an ovary to begin its path down one of a woman’s fallopian tubes to the uterus in preparation for conception. This process only occurs after puberty when hormones cause a resumption of meiosis for one to several primary oöcytes each month.

ovulation

The place in a woman’s reproductive system where conception usually occurs.

fallopian tubes

Genes that are on the same chromosome and subsequently are inherited together as a package unless crossing-over separates them.

linked genes

The exchange of genetic material (DNA) between homologous chromosomes at the beginning of meiosis. This results in sperm and ova with greater genetic diversity due to a recombination of genes. Specifically, a portion of a chromosome is broken and reattached on another chromosome.

crossing-over

Genes that are linked together because they are carried by a sex chromosome.

sex-linked genes

Genes that are linked together because they are carried by an X chromosome.

X-linked genes

Genes that are linked together because they are carried by an Y chromosome.

Y-linked genes

The largest sex chromosome in humans. This chromosome is inherited by both males and females.

X chromosome

The names for the two sex chromosomes of females.

XX

The names for the two sex chromosomes of males.

XY

An X-linked genetically inherited recessive disease in which one or more of the normal blood clotting factors is not produced. This results in prolonged bleeding from even minor cuts and injuries. It most often afflicts males.

hemophilia

Twins that are mostly identical genetically because they result from one zygote splitting into two separate ones within a few days after conception.

monozygotic

Twins that share their mother's uterus during gestation but come from two different eggs fertilized with different sperm. They are not genetically identical.

dizygotic

An individual who came from two zygotes that fused together. If one of the zygotes is male and the other female, the individual will most likely be a hermaphrodite.

chimera