MBB 446 Lecture Glossary

Question 1

diploid

Answer 1

organism with 2 copies per gene

Question 2

allele

Answer 2

different version of a gene

Question 3

Dominant

Answer 3

Version of allele that expresses its phenotype when heterozygous

Question 4

recessive

Answer 4

Unexpressed allele when heterozygous–only expressed when homozygous

Question 5

phenotype

Answer 5

expression of the genotype

Question 6

homozygous

Answer 6

alleles within an organism are identical

Question 7

heterozygous

Answer 7

an organism carries two different alleles of a gene

Question 8

hemizygous

Answer 8

only one copy of the gene the second one being deleted as in X chromosomes in males

Question 9

SNP single nucleotide polymorphism

Answer 9

DNA sequence variant in a single nucleotide position. Must occure in > 1% of the population to be considered an SNP.

Question 10

Mutation

Answer 10

DNA sequence variant occurring in less than one percent of the population.

Question 11

Euploid karyotype

Answer 11

normal configuration of chromosomes; 22 autosome pairs + sex chromosomes in mammals

Question 12

Aneuploidy

Answer 12

deviation from the euploid karyotype

Question 13

Spectral Karyotype (SKY)

Answer 13

karyotype stained with different colours to aid identification of chromosomes

Question 14

Homogeneously Staining Region (HSR)

Answer 14

repeated rounds of reduplication of a chromosome segment fused head to tail in a long array

Question 15

Double Minute chromosomes (DMs)

Answer 15

chromosomal segments that have broken loose from their original sites and replicate autonomously to many copies per nucleus

Question 16

Gene amplification

Answer 16

The process whereby more copies of a gene are available for expression than should be ie HSR and DMs

Question 17

Germ line

Answer 17

The nucleic material of the sperm and egg

Question 18

Somatic mutations

Answer 18

Mutations affecting the genomes of cells everywhere else in the body

Question 19

constitutional DNA

Answer 19

The DNA in germ cells

Question 20

Histology; Histopahtology

Answer 20

microscopic examination of tissue sections

Question 21

neoplasia

Answer 21

new growth

Question 22

parenchyma

Answer 22

chyma = poured in; para = beside; the tissue of the tumour

Question 23

stroma

Answer 23

the extracellular matrix ECM in which other cells (connective; adipocytes; blood vessels; immune system cells) are embedded

Question 24

desmoplasia

Answer 24

the growth of fibrous or connective tissue ie scar tissue around surgery; the formation of abundant collagenous stroma stimulated by parenchymal cells

Question 25

Primary tumour

Answer 25

site where cancer begins

Question 26

metastases

Answer 26

the spread of cancer to secondary sites throughout the body; often can be traced back to the primary tumor

Question 27

benign

Answer 27

local growth; no invasion of adjacent tissues

Question 28

malignant

Answer 28

invasion of nearby tissues; also metastases

Question 29

Ectoderm

Answer 29

The outermost (distal) of the three germ layers in the embryonic stage (skin)

Question 30

Endoderm

Answer 30

The innermost (proximal) of the three germ layers in the embryonic stage (becomes internal organs; lung liver gallbladder pancreas esophagus stomach intestines)

Question 31

Mesoderm

Answer 31

The middle layer of the three germ layers in the embryonic stage (ovaries)

Question 32

basement membrane

Answer 32

specialized type of ECM providing structural support for the epithelial cells; barrier between epithelial cells and the underlying stroma (supporting connective tissue) aka basil lamina

Question 33

Carcinoma

Answer 33

malignancy of the epithelial cells (derive from all three germ layers) 90%

Question 34

Sarcoma

Answer 34

malignancy of the connective tissues (derive from the mesenchymal cell types; fibroblasts secrete collagen adipocytes store fat osteoblasts form bone myocytes form muscle) 2%

Question 35

Leukemia

Answer 35

malignancy of the blood forming (hematopoietic) cells 8% w Lymphoma

Question 36

Squamous cell carcinomas

Answer 36

Originating from epithelial cells that from protective cell layers

Question 37

Adenocarcinomas

Answer 37

Originating from specialized epithelial cells that secrete substances into ducts or cavities that they line

Question 38

leiomyosarcoma

Answer 38

arises from cells that form smooth muscle

Question 39

Lymphoma

Answer 39

tumor of the lymphoid lineages (B & T lymphocytes); aggregate toform solid tumor masses found in lymph nodes

Question 40

Neuroectodermal tumors

Answer 40

arise from cells that form components of the central and peripheral nervous system; from the ectodermal layer 1.3%

Question 41

transdifferentiation

Answer 41

switching of tissue lineage and resulting acquisition of an entirely new set of differentiated characteristics

Question 42

epithelial-mesenchymal transition EMT

Answer 42

epithelial cells often change shape and gene expression programs and take on attributes of nearby stromal cells of mesenchymal origin

Question 43

anaplastic tumors

Answer 43

tumors have losta ll tissue-specific differentiated traits of their normal precursor tissues. Cells have dedifferentiated; no longer possible to use histopathology to id tissue of origin