Biology Exam 4

when damage occurs in the tumor suppressor genes and proto-oncogenes…

cells look and act differently

cells normally stop dividing when they run out of room this is called…

contact inhibition

… can cause a loss of contact inhibition (cells pile up)

genetic damage

a mass of abnormal cells is a…

tumor

benign tumor is..

not cancer

benign tumor is unrelated…

cell division

For benign tumors the cells are abnormal (… genetic errors) but the tumor cells still look like the original cell type and do not interfere with surrounding cells.

some

Malignant Tumor is..

is cancer

malignant tumor cells contain…so they do not look like the original type. They also invade and interfere with surrounding cells.

many genetic errors

… model of cancer development

multiple-hit

cancer develops when mutations accumulate in..

proto-oncogenes and tumor supressor genes

cells normally remain connected to a point of attachment this is called…

anchorage dependance

cells with genetic damage/errors can lose anchorage dependence which means cells…

break away and travel to new locations

…cancer cells break away from a tumor and establish new malignant tumors in the other part of the body.

metastasis

metastasis can occur in the …

blood stream or the lymphatic system

normally mitosis continues for a programmed number of rounds and then ends (even if…

cells have enough room and resources

…a population of cells that started with a single cell

cell line

so a normal cell line is…

finite

cells with a lot of genetic errors are not limited to…

a programmed number of divsions

genetically damaged cell lines can keep dividing… if they have resources and room

indefinitely

cancer cells do not have a programed…

end point where mitosis stops, they are immortal

the first human cell line grown in a lab began in…

1951 with cervical cancer cells (HELA cell line)

HELA cell line: named for…, the source of the cervical cancer cells

Henrietta lacks

since 1951, more than … tons of HELA cells have been grown in labs

50 million

HELA cells have been the basis for more than 17,000 patents, for the

polio vaccines, cancer and HIV treatment, parkinson’s disease and mapping the genetic code.

HELA cells were sent…

with the first humans who went up to space

cells dividing out of control can disrupt multiple organs and interfere with their essential life-support functions

this is what makes cancer dangerous

what are some risk factors for cancer

aging
family history
smoking
uv radiation
some viruses

why does aging increase the risk of cancer

-mutations accumulate over time
-the hit model is when this happens

family history risk in cancer

BRCA1 and BRACA2 are tumor suppressor genes, some versions of these contain mutations that make the risk of cancer higher than normal

smoking risk in cancer

cells exposed to smoke experience hundreds of extra mutations

UV radiation (ultraviolet) (carcinogenic-cancer causing) risk in cancer

UV radiation penetrates the skin and damages cells in DNA, UV radiation changes the shape of the double helix

most viruses reproduce by taking over the

ribosomes of a host cell and using them to make more viruses

but some viruses (oncoviruses) also insert their genes into the chromosomes of a host cell…

this can damage important genes like tumor suppressors and proto-oncogenes)

viruses that can cause cancer are called…

oncoviruses

genes inside a protein shell are called…

capsids

HPV infections are common…

nearly everyone will get HPV at one point

there are more than…(types) of HPV

100 strains

many strains are not dangerous but some( especially…) are oncoviruses

type 16 and 18

Harald zur Hausen got the Nobel prize for what…

his discovery that HPV causes cervical cancer in 2008

when were HPV vaccines introduced

in 2006

2006-2016: HPV infections by oncoviruse strains fell by…

90% by teenage girls

HPV vaccination is… effective against oncorovirus strains and genital warts in males and females

90-100%

what two cancer treatments are there…

chemotherapy
radiation

medication travels through the bloodstream and kills rapidly dividing cells

chemotherapy

a beam of high energy destroys the DNA of rapidly dividing cells

radiation

both kill rapidly dividing cells, but…

not all rapidly dividing cells are cancer

these treatments have side affects because they…

kill some normal cells

is it possible for cancer treatments to target cancer cells specifically?

Yes.
1. drug that stops angiogenesis
2. (immunotherapy)
3. gene editing tool

drug that stops angiogenesis makes…

the drugs prevent tumor cells from receiving enough oxygen and nutrients

James P. Allison and Tasuku Honjo got the noble prize for…

immunotherapy in 2018

CRISPR is a… that can be used to correct DNA sequence

gene-editing tool

Emmanuelle Charpentier and Jennifer Doudna won the noble prize for

CRISPR, the revolutionary “scissors” in 2020

radiologist can identify cancer on…

images

pathologist can identify cancer with…

microscopes

what are stem cells…

unspecialized cells that have not “yet” decided what kind of cell they will be

how are stem cells different then other cells?

other cells are specialized

specialization is necessary for a …

zygote to develop into a organism

…is the technical term for specialization

differentiation

a specialized (differentiated) cell:

-is committed to a certain function
-divides to produce more cells of the same type

stem cells are…

unspecialized (undifferentiated)

stem cells replenish themselves and serve as the… of specialized cells

source

3 main types of stem cells are…

multipotent
totipotent
pluripotent

limited flexibility is know as the

multipotent stem cells

can specialize into several different types of somatic cells (body cells)

ex. bone marrow
ex. umbilical chord

multipotent

multipotent stem cells that are the source of all blood cells

bone marrow

multipotent stem cells are found in most…

body tissues

… are cells that work together as a unit

tissues

stem cells with complete flexibility

totipotent stem cells

can specialize into any type of somatic cell in an organism, plus cells of the placenta

totipotent stem cell

stem cells with high flexibility is

pluripotent stem cells (embryonic stem cells)

can specialize into any type of somatic cell in an organism( but cannot individually develop into a placenta)

pluripotent stem cells

… exist inside the hollow ball of about 200 cells (embryo) that forms about 5 days after a zygote forms

pluripotent stem cells

…can give rise to any type of somatic cells

pluripotent stem cells

when were pluripotent stem cells first isolated from human embryos

1998

…can produced specialized cells to cure patients who have Parkinsons disease or a sport injury

embryonic stem cells

potential application of embryonic stem cells:

-better understanding of how diseases develop
-treating curing diseases
-testing drugs for safety and efectiveness

how would medical researchers have access to these cells?

pluripotent stem cell lines are developed by:

1. using excess IVF embryos

2. nuclear transfer (therapeutic cloning)

3. reformat somatic cells to become pluripotent

step of IVF

-IVF (in Vitro fertilization) is a treatment for infertility

-egg and sperm are combined in a lab

-the zygote divides to form an embryo that is transferred to a patients uterus

first human IVF birth was in

1978

more than … babies have been born as a result of IVF

8 million

Robert G Edwards won the Noble Prize for…

IVF ( in vitro fertilization) 2010

a single IVF attempt does not always result in pregnancy so that means…

multiple embryos are usually produced an frozen for a couple hoping to achieve pregnacy

some couples donate their excess embryos for…

medical research on disease treatment and cures

chemicals that cause cells to differentiate by activating or silencing genes

growth factors

using excess IVF embryos requires…

screening to find a match for a specific patient

a source of customized pluripotent cells that will match a patient

nuclear transfer

nuclear transfer can also be used for

reproduction cloning

producing an organism that is genetically identical to another organism

reproduction cloning

all of the cells of an organism contain the same genetic information so specialized cells can be reformatted to become iPS cells (induces pluripotent stem cells)

reformat somatic cells to become pluripotent

John B. Gurdon and Shinya Yamanaka won the noble prize for what

mature cells could be reprogrammed 2012

engineered viruses are used to introduce genes that…

turn silenced genes back on (“reformatting” cells)

iPS cells can also become…

egg and sperm cells

are protective caps at the ends of all chromosomes

telomeres

telomeres are made of…

repetitive DNA

HeLa cell lines are the source of

cervical cell lines

HPV is

Human papillomavirus is the most common sexually transmitted infection (STI).

with each division the telomeres…

shorten

when the telomeres run out…

cell division stops

what if telomere shortens too quickly…

this can cause projeria