THE HUMAN LIFE CYCLE. CELLS DIVIDING IN AN EARLY EMBRYO.
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Transcript of THE HUMAN LIFE CYCLE. CELLS DIVIDING IN AN EARLY EMBRYO.
THE HUMAN LIFE THE HUMAN LIFE CYCLECYCLE
CELLS DIVIDING IN AN CELLS DIVIDING IN AN EARLY EMBRYOEARLY EMBRYO
THE THE CELL CYCLECELL CYCLE = = THE DAY-TO-DAY LIFE THE DAY-TO-DAY LIFE OF A CELLOF A CELL
CELL NUCLEICELL NUCLEI
CHROMOSOMESCHROMOSOMES IN THE CELL NUCLEUS IN THE CELL NUCLEUS- CHROMOSOMES ARE MADE OF DNA- CHROMOSOMES ARE MADE OF DNA
CHROMOSOMES CHROMOSOMES DUPLICATE BEFORE DUPLICATE BEFORE CELLS DIVIDECELLS DIVIDE
A DIVIDING CELLA DIVIDING CELL
CELL DIVISION - CELL DIVISION - MITOSISMITOSIS
CELL DIVISION - CELL DIVISION - MITOSISMITOSIS
INTERPHASEINTERPHASE
PROPHASEPROPHASE
METAPHASEMETAPHASE
ANAPHASEANAPHASE
TELOPHASETELOPHASE
CELL DIVISION - CELL DIVISION - MITOSISMITOSIS
SKIN CELLS ARE SKIN CELLS ARE CONSTANTLY DIVIDINGCONSTANTLY DIVIDING
BREAST CELLSBREAST CELLSNORMAL CANCEROUSNORMAL CANCEROUS
COMPARISON OF COMPARISON OF MITOSIS AND MEIOSISMITOSIS AND MEIOSIS
MEIOSISMEIOSIS – MEIOSIS I – MEIOSIS I
MEIOSIS – MEIOSIS IIMEIOSIS – MEIOSIS II
DOWN’S SYNDROMEDOWN’S SYNDROME
Characteristics of Down’s Characteristics of Down’s SyndromeSyndrome There are over 50 clinical signs of Down syndrome, but it is rare to find all or even most of them in There are over 50 clinical signs of Down syndrome, but it is rare to find all or even most of them in
one person. Some common characteristics and down syndrome facts include:one person. Some common characteristics and down syndrome facts include:
Poor muscle tonePoor muscle tone
Slanting eyes with folds of skin at the inner corners (called epicanthal folds)Slanting eyes with folds of skin at the inner corners (called epicanthal folds)
Hyperflexibility (excessive ability to extend the joints)Hyperflexibility (excessive ability to extend the joints)
Short, broad hands with a single crease across the palm on one or both handsShort, broad hands with a single crease across the palm on one or both hands
Broad feet with short toesBroad feet with short toes
Flat bridge of the noseFlat bridge of the nose
Short, low-set earsShort, low-set ears
Short neckShort neck
Small headSmall head
Small oral cavitySmall oral cavity
Short, high-pitched cries in infancy. Short, high-pitched cries in infancy.
MATERNAL AGE vs. MATERNAL AGE vs. RATE OF DOWN’S RATE OF DOWN’S
SYNDROMESYNDROME
KARYOTYPINGKARYOTYPING = a technique to visualize the = a technique to visualize the chromosomes and number of chromosomes in a chromosomes and number of chromosomes in a dividing celldividing cell
HUMAN FEMALE HUMAN FEMALE KARYOTYPEKARYOTYPE
HUMAN MALE HUMAN MALE KARYOTYPEKARYOTYPE
DOWN’S SYNDROME DOWN’S SYNDROME KARYOTYPEKARYOTYPE
COMPARISON OF COMPARISON OF MITOSIS AND MEIOSISMITOSIS AND MEIOSIS
NONDISJUNCTIONNONDISJUNCTION = failure of = failure of chromosomes to separate chromosomes to separate during meiosisduring meiosis
FERTILIZATION AFTER FERTILIZATION AFTER NONDISJUNCTION IN NONDISJUNCTION IN AN EGGAN EGG
AmniocentesisAmniocentesis = sampling the = sampling the amnionic fluid around the fetus amnionic fluid around the fetus for fetal cellsfor fetal cells
Chorionic Villi SamplingChorionic Villi Sampling = = sampling the placental cells sampling the placental cells which have the same DNA as which have the same DNA as fetal cellsfetal cells
KLINEFELTER’S SYNDROMEKLINEFELTER’S SYNDROME (XXY) = due to nondisjunction (XXY) = due to nondisjunction of sex chromosomesof sex chromosomes
Due to fertilization with an egg or sperm that has an extra X chromosome
TURNER’S SYNDROMETURNER’S SYNDROME (XO) = (XO) = due to nondisjunction of sex due to nondisjunction of sex chromosomeschromosomes
Due to fertilization with an egg or sperm lacking an X chromosome
Proteins Perform Most Proteins Perform Most Cell FunctionsCell Functions