Genetic Terminology

Question 1

Allele

Answer 1

Allele is a variant or alternate form of gene. An example: there are 2 alleles for the gene for dimples in humans. If you inherit one allele, you have dimples; if you inherit the other, you don’t have dimples.

Question 2

Amino Acid

Answer 2

The basic building blocks of proteins. There are 20 amino acids present in the human body.

Question 3

Breeding population

Answer 3

A group whose members mate with each other and usually not with outsiders.

Question 4

Base or bond

Answer 4

In genetics, a chemical bond in DNA & RNA that links to another chemical bond in a specific pattern. In DNA, “A” (Adenine) always links to “T” (thymine). “C” (cytosine) always links to “G” (guanine). In RNA “A” links with “U”. “G” and “C” still link together.

Question 5

Complementary Opposite

Answer 5

In DNA, A and T are known as complementary opposites, as are C & G.

Question 6

Crossing-over

Answer 6

Homologous chromosomes pair up during meiosis, come close to each other & exchange segments of DNA. Result: a reshuffling of the genes from generation to generation.

Question 7

Cytoplasm

Answer 7

The gel-like substance enclosed within a cell

Question 8

Diploid cells

Answer 8

Cells that have two (2) sets of chromosomes

Question 9

Dominant

Answer 9

A trait that is expressed even if only one allele for it is pre3sent. Note that dominant traits are NOT superior or stronger, despite the popular idea of dominant as powerful.

Question 10

Gamete

Answer 10

A kind of sex cell

Question 11

Gene pool

Answer 11

All the genes carried within a breeding population

Question 12

Genome VS genotype

Answer 12

The genome is the genetic make up of an individual or species; genotype is an individual’s set of alleles

Question 13

Haploid

Answer 13

A sex cell that has half the normal number of chromosomes

Question 14

Heterozygous

Answer 14

Having two (2) different alleles.

Question 15

Homozygous

Answer 15

Having two (2) of the same alleles.

Question 16

“Master” genes

Answer 16

Genes that set off a cascade (καταρράκτης) of other genes

Question 17

Meiosis

Answer 17

The production of sex cells or gametes that have half the full complement of chromosomes

Question 18

Mendelian trait

Answer 18

Also called a monogenic trait. A trait that is coded for by only two (2) alleles so that the individual can only inherit one allele or the other (eg dimples or no dimples).

Question 19

Mitochondria

Answer 19

Organelle (cell body) containing DNA inherited only from the mother’s line

Question 20

Mitosis

Answer 20

The division of a cell into two (2) daughter cells that are exactly like the parent cell

Question 21

Mutation

Answer 21

A permanent change in the DNA sequence of a gene

Question 22

Nucleotide

Answer 22

Building a block of DNA; contains sugar, phosphate and a nitrogen base

Question 23

Nuclear membrane (nuclear envelope)

Answer 23

The layers of molecules that enclose the nucleus and keep DNA from passing into the cytoplasm in the rest of the cell

Question 24

Organelle

Answer 24

The small bodies within the cytoplasm that serve various functions in the cell

Question 25

Phenotype

Answer 25

The outward, visible manifestation (εκδήλωση) of a trait; the physical appearance of a trait

Question 26

Proteins

Answer 26

The enzymes, hormones, antibodies, antigens, nutrients & chains of amino acids that structure tissues, carry vital gases to tissues and carry our particular bodily functions

Question 27

Protein synthesis

Answer 27

The process of making the complex chemicals (proteins) that are necessary for the functioning and repair of tissues and many other bodily activities

Question 28

Punnett square

Answer 28

A mathematical tool, still used in genetic counseling, that takes the form of a diagram. The diagram shows the percentages of each genotype tha may appear in a generation of offspring, given the particular alleles carried by the parents.

Question 29

Random Assortment (Independent assortment)

Answer 29

Meiotic cell division that results in each gamete carrying only one rather than a pair of chromosomes. It’s matter of change as to whether offspring inherit the mother’s of the father’s chromosome for each of the pairs.

Question 30

Recessive

Answer 30

A trait that exists in the genotype but doesn’t appear in the phenotype unless the individual inherits two (2) of the same recessive alleles.

Question 31

Recombination

Answer 31

The process of reshuffling genetic material that occurs during gamete formation. It refers to random assortment and crossing-over.

Question 32

Ribosome

Answer 32

Organelle (cell body) where RNA chains amino acids into proteins

Question 33

RNA

Answer 33

A single stranded molecule involved in carrying out DNA’s instructions.

Question 34

mRNA

Answer 34

Messenger RNA, the strands of molecules (μόρια) that carry DNA’s code outside the nucleus. mRNA links up with tRNA at the ribosomes in a particular pattern: A to U, U to A, C to G, G to C.

Question 35

tRNA

Answer 35

Transfer RNA, the strands of molecules that “translate” or “read” mRNA’s code at the ribosomes. tRNA uses mRNA code to chain amino acids together until they form a protein. Together amino acids at the ribosome to form proteins.

Question 36

Somatic cell

Answer 36

Body cell

Question 37

Zygote

Answer 37

Fertilized sex cell; fertilized gamete