week 2: Human cells, cancer Flashcards
what is gametogenesis?
the production of the gametes
what is spermatogenesis?
the formation of sperm. it is continuous and prolific
hundreds of millions produced each day. each sperm takes about seven weeks to develop.
oogenesis
the development of a mature egg.
this is a prolonged process.
immature eggs form in the female embryo but do not complete their development for years later.
what is fertilization?
it is the formation of a diploid zygote from the haploid egg and sperm.
what is the cleavage
a period with rapid mitotic division without growth.
what is a morula
the compact mass of cells after fertilization.
what is gastrulation?
the cells of the blastula (fluid filled cell) are rearranged into a three layered embryo called the gastrula.
What are the three germ layers produced during gastrulation?
- ectoderm
- mesoderm
- endoderm
describe the ectoderm germ layer
the epidermis of the skin, the nervous system (including brain) and sensory organs.
describe the mesoderm germ layer
the skeleton, muscles, blood vessels, heart, blood and kidneys
describe the endoderm germ layer
lining of internal organs; including those of the digestive system, respiratory system, liver and pancreas.
what happens during the first trimester?
all the major structures are present by 8 weeks, and the embryo is called a fetus
what happens during the second trimester
(3 point)
- the fetus grows and is very active
- the mother may feel fetal movements.
- the uterus grows enough for the pregnancy to become obvious
what happens during the third trimester
the fetus grows and fills the space within the embryonic membranes.
what are the 4 adult tissue types
- epithelial tissue
- connective tissues
- muscle tissue
- nerve tissue
describe epithelial tissue
tightly packed cells, covers internal and external surfaces
describe connective tissue
loosely packed cells surrounded by abundant extracellular matrix
describe muscle tissue
specialized for movement
what is nerve tissue for?
used for the transmission of nerve impulses
what type of cell has the ability to continuously divide and differentiate into various other kinds of cells/tissues
Stem cells.
what are embryonic stem cells?
- cells taken from the inner cell mass of the blastocyst
- they are pluripotent
what are Adult stem cells?
-stem cells from adults needed for normal growth and repair.
-adult stem cells are multipotent.
describe and give examples of totipotent cell type
each cell can develop into a new individual
cells from early embryos (1-3 days)
describe and give examples of pluripotent cell type
cells can differentiate into any cell type
some cells of the blastocyst (5-14 days)
describe and give examples of multipotent cell type
have the ability to differentiate into all cell types within one particular lineage/cell group
fetal tissue, cord blood, and adult stem cells
explain Induced Pluripotent Stem Cells (IPS’s)
obtained from adult somatic cells
reprogrammed to act like embryonic stem cells
created in 2007
the cells are “dedifferentiated” by genetic modification
why is stem cell research important?
(3 points)
- stem cells can replace diseased or damaged cells
- stem cells allow us to study development and genetics
- stem cells can be used to test different substances (drugs and chemicals)
explain the process of reproductive cloning
Genetic material (nucleus from embryonic, fetal, or adult cell) is removed and placed into an unfertilized egg or embryo, whose nucleus has been removed.
what is the result if the genes that regulate cell growth and division mutate?
cancerous cells may develop
what are the three types of cancer?
carcinomas,
sarcomas,
leukemias and lymphomas.
what type of cancer constitutes 90% of cancers and are cancers of
epithelial cells
carcinomas
what type of cancer is rare and consist of tumors of connective tissues (connective tissue, muscle, bone etc.)?
sarcomas
what are the characteristics of lymphomas and leukemias?
constitutes 8% of tumors.
Leukemias arise from blood forming cells
lymphomas arise from cells of the immune system (T and B cells).
describe a benign tumor
do not spread from their site of origin but can crowd or squash surrounding area (eg brain tumor)
describe malignant tumor
can spread from the original site and cause secondary tumors. this is called metastasis
what is a somatic mutation?
mutations that occur in any cell of the body except from the germ cells.
this form of cancerous gene is not passed on to offspring.
what are the two types of cancer critical genes?
- tumor suppressor genes
- oncogenes
what ways can proto-oncogenes be converted to oncogenes?
(3 points)
- movement of DNA within genome
- amplification of proto-oncogene
- point mutation in the proto-oncogene or its control elements
what is the Ras protein?
acts as a signaling protein at an early stage of a pathway which stimulates cell proliferation.
what prevents a cell from passing on mutations due to DNA damage?
the p35 gene.
name 5 treatments for cancer
surgery combined with radiation or chemotherapy
immunotherapy
cancer fighting vaccines
gene therapy
stem cell research
