CANCER AND BIOTECHNOLOGY

CHAPTER 19 and Chapter 21

DNA AND BIOTECHNOLOGY

DNA

A MACROMOLECULE THAT CONTAINS THE INFORMATION NEEDED TO BUILD PROTEINS

AN ORGANISM’S STRUCTURE IS THE RESULT OF ALL THE DIFFERENT PROTEINS THAT ITS DIFFERENT CELLS MAKE

GENE

A SEGMENT OF DNA THAT CONTAINS THE RECIPE FOR A PROTEIN

A PROTEIN IS A POLYMER MADE OF AMINO ACIDS CONNECTED TOGETHER

CHROMOSOME

A LONG PIECE OF DNA CAN BE EXTENDED (CHROMATIN)

SO IT CAN BE READ CAN BE COMPACTED

(CHROMOSOME) SO IT CAN BE EASILY MOVED AROUND WHEN THE CELL DIVIDES

CHROMOSOMES

CHROMOSOMES ARE RECIPE BOOKS MADE UP OF THOUSANDS OF GENES (RECIPES FOR PROTEINS)

THE SUM OF ALL THE RECIPES IS THE ORGANISM

DNA STRUCTURE

A POLYMER COMPOSED OF UNITS CALLED NUCLEOTIDES

NUCLEOTIDE- PHOSPHATE, SUGAR, BASE

DNA BASES= A, T, C, G

DNA CONT.

DNA IS A DOUBLE STRANDED HELIX (SPIRAL)

THE 2 STRANDS ARE HELD TOGETHER BY HYDROGEN BONDS BETWEEN COMPLEMENTARY BASES

COMPLEMENTARY BASE PAIRING = A-T AND G-C

REPLICATION

COPYING THE DNA BEFORE CELL DIVISION

1. THE HELIX UNZIPS

2. DNA POLYMERASE INSERTS COMPLEMENTARY NUCLEOTIDES ACROSS FROM THE PARENT STRAND

WE HAVE 2 identical double stranded DNA MOLECULES

RNA

ALSO A POLYMER MADE UP OF NUCLEOTIDES

DIFFERENT SUGAR, SINGLE STRANDED

U INSTEAD OF T, A-U AND G-C COMPLEMENTARY RNA COPIES ARE

MADE BY RNA POLYMERASE

3 TYPES OF RNA

rRNA- WILL BECOME PART OF RIBOSOME

mRNA- A DISPOSABLE RNA COPY OF A GENE

tRNA- TRANSFERS THE CORRECT AMINO ACID TO THE RIBOSOME WHERE IT WILL BE CONNECTED IN THE CORRECT ORDER TO FORM A PROTEIN

MAKING A PROTEIN

2 STEPS

1. MAKE AN RNA COPY (mRNA) OF THE GENE FOR THE PROTEIN THE CELL NEEDS= TRANSCRIPTION

2. THE RNA COPY GOES TO THE RIBOSOME WHERE ITS INFORMATION IS USED TO CONNECT THE CORRECT AMINO ACIDS (AA’S) TOGETHER TO MAKE THE PROTEIN= TRANSLATION

DNA CODE

IT TAKES A SET OF 3 BASES (CODON) TO CODE FOR ONE Amino Acid (PROTEIN INGREDIENT)

TRANSCRIPTION- MAKES A COMPLEMENTARY RNA COPY OF A GENE- RNA POLYMERASE

TRANSCRIBE 30 BASES= ENOUGH INFO FOR 10 INGREDIENTS (10 AA’S)

TRANSLATION

THE mRNA MOVES TO THE RIBOSOME WHERE IT IS READ AND THE CORRECT PROTEIN IS MADE

THE RIBOSOME ACTS AS THE COUNTERTOP WHERE THE mRNA IS READ AND THE CORRECT INGREDIENTS (AA’S) ARE MIXED (CONNECTED) TOGETHER

tRNA’s are gophers

EACH DIFFERENT tRNA HAS A 3 BASE ANTI-CODON SEQUENCE ON ONE END

THE OTHER END CARRIES A SPECIFIC AMINO ACID

WHEN THIS SEQUENCE IS COMPLEMENTARY TO THE mRNA CODON- THAT tRNA WILL RUSH IN AND DROP OFF ITS AA

AA’S

AS THE CORRECT AMINO ACIDS ARE DROPPED OFF IN THE CORRECT ORDER BY THE tRNA’S (MATCHING THEIR ANTICODONS WITH THE mRNA CODONS) THEY ARE CONNECTED TOGETHER BY PEPTIDE BONDS TO FORM A POLYPEPTIDE= THE PROTEIN

BIOTECHNOLOGY

THE USE OF GENETIC ENGINEERING TO PRODUCE A DESIRED PRODUCT

GENETIC ENGINEERING= THE ALTERATION OF THE GENOME OF VIRUSES, BACTERIA AND OTHER CELLS

RESULTS

TODAY GENETICALLY ENGINEERED ORGANISMS MAKE INSULIN, GROWTH HORMONE AND MANY OTHER DRUGS WHICH TREAT CANCER AND CIRCULATORY DISORDERS.

PRODUCING A PROTEIN

1. CUT THE GENE THAT CODES FOR THE DESIRED PROTEIN OUT OF A HUMAN CELL

2. SPLICE THE GENE INTO A VECTOR WHICH TRANSFERS THE GENE TO THE HOST CELL

3. THE HOST CELL WILL TRANSCRIBE AND TRANSLATE THE GENE AND GIVE US THE PROTEIN

FORENSICS

A SEQUENCE OF DNA IS PRECISELY CUT OUT OF A HOST CELL WITH A RESTRICTION ENZYME. IT IS THEN COPIED HUNDREDS OF TIMES.

USE ANOTHER RESTRICTION ENZYME TO CHOP IT UP

GEL ELECTROPHORESIS- PROCESS THAT SEPARATES THE CHOPPED UP SEGMENTS BASED ON THEIR SIZES

FORENSICS

IDENTICLE DNA WILL FRAGMENT IN THE SAME LOCATION WHICH WILL PRODUCE THE SAME FRAGMENT PATTERNS ON A GEL

DNA FROM DIFFERENT PEOPLE WILL FRAGMENT AT DIFFERENT PLACES AND THE FRAGMENT PATTERNS WILL BE DIFFERENT

TRANSGENIC ORGANISMS

BACTERIA- MAKE CHEMICALS AND DRUGS (MAKE HUMAN INSULIN FOR DIABETICS)

PLANTS- RESIST INSECTS, DISEASES AND HERBICIDES, GROW BETTER

ANIMALS- BIGGER (PRODUCE GROWTH HORMONE), PRODUCE DRUGS IN THEIR MILK.

GENE THERAPY

GIVES GOOD GENES TO SOMEONE WITH BAD GENES

DNA PROBES

SMALL RADIOACTIVE SINGLE STRANDED DNA SEQUENCES MIXED WITH CHROMOSOME

CAN IDENTIFY THE LOCATION OF GENES ON A CHROMOSOME BY HYBRIDIZING (MATCHING) WITH THEM

USED TO IDENTIFY GENETIC DISEASES

CANCER

CAUSES

CARCINOGEN- THREE TYPES

RADIATION- X-RAYS, ULTRAVIOLET= UV (SUN), RADON

ORGANIC CHEMICALS- TOBACCO, HIGH FAT DIET, POLLUTANTS, DYES

VIRUSES- HEPATITIS B- LIVER CANCER, GENITAL WARTS- CERVICAL CANCER

HEREDITY

CERTAIN TYPES CAN BE INHERITED AS MUTATIONS

BREAST, LUNG AND COLON- IF A FIRST DEGREE RELATIVE HAS IT THEN YOUR RISK INCREASES 2-3x

SOME LESSER KNOWN CANCERS CAN BE INHERITED AS A DOMINANT ALLELE

IMMUNODEFICIENCIES

OUR IMMUNE SYSTEM SOMETIMES RECOGNIZES CANCER CELLS AS “BAD” AND ATTACKS THEM.

IF THE IMMUNE SYSTEM IS WEAK (AIDS OR IMMUNOSUPPRESSIVE DRUGS) THE BODY IS LESS LIKELY TO ATTACK CERTAIN CANCERS.

CARCINOGENESIS

THE DEVELOPMENT OF CANCER

1. INITIATION- A MUTATION

2. PROMOTION- CELLS DIVIDE QUICKLY

3. PROGRESSION- CANCER CELLS INVADE BLOOD OR LYMPH VESSELS AND SPREAD TO OTHER PARTS OF THE BODY

CANCER CELLS UNDER THE MICROSCOPE

NO DIFFERENTIATION- DISORGANIZED LAYERING, GENERIC ROUND CELLS

ABNORMAL NUCLEI- ENLARGED NUCLEUS, EXTRA OR MISSING CHROMOSOMES

FORM TUMORS- CELLS KEEP DIVIDING, A MASS OF CELLS IS PRODUCED

TUMORS

BENIGN- TUMOR DOES NOT SPREAD, ENCAPSULATED

MALIGNANT- TUMOR SHOWS SIGNS OF SPREADING, HAS ITS OWN BLOOD SUPPLY

ANGIOGENESIS

THE FORMATION OF NEW BLOOD VESSELS TO SUPPLY A TUMOR WITH OXYGEN AND NUTRIENTS

CANCER CELLS RELEASE A GROWTH FACTOR WHICH PROMOTES THE GROWTH OF NEW BLOOD VESSELS

METASTASIS

NEW TUMORS GROW IN LOCATIONS AWAY FROM THE PRIMARY TUMOR

CANCER CELLS MUST PRODUCE A PROTEINASE ENZYME THAT EATS THROUGH SURROUNDING TISSUE.

WHEN A BLOOD OR LYMPH VESSEL IS REACHED, CANCER CELLS ARE CARRIED ELSEWHERE WITH THE FLOW OF THESE FLUIDS

PROGNOSIS= LIKELY OUTCOME

DEPENDS ON:

1. IF THE PRIMARY TUMOR HAS INVADED SURROUNDING TISSUE

2. IF LYMPH NODES WERE INVADED

3. IF THERE ARE TUMORS IN OTHER PARTS OF THE BODY

GENETIC BASIS

PROTO-ONCOGENES- NORMAL GENES WHICH CODE FOR PROTEINS WHICH REGULATE CELL DIVISION

A MUTATION CAN CHANGE THESE GENES INTO ONCOGENES.

ONCOGENES- CAUSE CELL TO DIVIDE REPEATEDLY

OTHER GENES

TUMOR SUPPRESSOR GENES- CODE FOR REGULATORY PROTEINS THAT ACT TO SLOW DOWN OR PREVENT UNNECESSARY CELL DIVISION LIKE A BRAKE

IF THESE “BRAKES” ARE DAMAGED, THEN CELL DIVISION MAY GET OUT OF CONTROL

STATISTICAL CHANCES

1 OF EVERY 3 PEOPLE WILL DEVELOP CANCER AND 1 OF EVERY 4 WILL DIE FROM IT.

DIAGNOSIS

SCREENING TESTS CERVICAL- PAP SMEAR- LOOKED AT

UNDER MICROSCOPE BREAST- SELF EXAM, MAMMOGRAM COLON- DIGITAL EXAM (FINGERS

FEEL FOR RECTAL CANCER), SIGMOIDOSCOPY, STOOL BLOOD TEST, BARIUM ENEMA / X-RAY.

SCREENING TESTS

LEUKEMIA- BLOOD TESTS BLADDER- URINALYSIS FOR BLOOD

OR CANCER CELLS

TUMOR MARKER TESTS

CANCER CELLS SOMETIMES PRODUCE FOREIGN CHEMICALS THAT SHOW UP IN BLOOD TESTS

MEASURING THESE CHEMICALS CAN INDICATE THE PRESENCE OR PROGRESSION OF CANCER (PROSTATE CELLS MAKE PSA- OLDER MEN SHOULD GET A PSA TEST)

HIGH PSA IN BLOOD MEANS OVERACTIVE PROSTATE CELLS- COULD BE CANCER

GENETIC TESTS

LOOK AT DNA SEQUENCES OF SPECIFIC GENES, USEFUL FOR DETERMINING CANCER RISKS LONG BEFORE A TUMOR DEVELOPS

OTHER TESTS

NEEDLE BIOPSIES DIRECTLY SAMPLES LUMP AND THEN SENT FOR MICROSCOPIC EXAMINATION

CAT AND MRI SCANS ULTRASOUND

TREATMENT

SURGERY- REMOVES CANCEROUS CELLS

RADIATION- KILLS CANCEROUS CELLS (AS WELL AS SOME NORMAL CELLS)

CHEMOTHERAPY- DRUGS THAT KILL CANCER CELLS BY DAMAGING DNA OR INTERFERING WITH WITH DNA SYNTHESIS

CHEMOTHERAPY

SPECIFIC DRUGS ARE USED ON SPECIFIC CANCERS

DIFFERENT COMBINATIONS OF DRUGS CAN BE USED TO AVOID RESISTANCE PROBLEMS

ANTIHORMONE THERAPY

BLOCKS HORMONES THAT CAN CAUSE CANCER

ESTROGEN- CAN LEAD TO CANCER OF BREAST

TESTOSTERONE- CAN LEAD TO CANCER OF PROSTATE

BONE MARROW TRANSPLANT

SOMETIMES USED TO TREAT BLOOD CANCERS (Leukemia) BECAUSE BLOOD CELLS ARE MADE BY BONE MARROW

1. REMOVE BONE MARROW AND THEN KILL THE CANCEROUS CELLS IN IT

2. MASSIVE CHEMO AND RADIATION TO KILL ALL CANCER CELLS IN THE BODY

3. REPLACE BONE MARROW

FUTURE TREATMENTS

IMMUNOTHERAPY- BREED TUMOR KILLING WHITE BLOOD CELLS OR HOOK CHEMOTHERAPY DRUGS TO ANTIBODIES WHICH WILL ATTACH TO TUMOR CELLS

ANTI ANGIOGENESIS- DRUGS THAT CUT OFF BLOOD SUPPLY TO TUMOR

ANTI METASTATIC- STOP ENZYME THAT ENABLES SPREAD

GENE THERAPY- REPLACE ONCOGENES WITH PROTO ONCOGENES