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THE HUMAN LIFE CYCLE. CELLS DIVIDING IN AN EARLY EMBRYO.

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Presentation on theme: "THE HUMAN LIFE CYCLE. CELLS DIVIDING IN AN EARLY EMBRYO."— Presentation transcript:

1 THE HUMAN LIFE CYCLE

2 CELLS DIVIDING IN AN EARLY EMBRYO

3 THE CELL CYCLE = THE DAY-TO-DAY LIFE OF A CELL

4 CELL NUCLEI

5 CHROMOSOMES IN THE CELL NUCLEUS - CHROMOSOMES ARE MADE OF DNA

6 CHROMOSOMES DUPLICATE BEFORE CELLS DIVIDE

7 A DIVIDING CELL

8 CELL DIVISION - MITOSIS

9

10 INTERPHASE

11 PROPHASE

12 METAPHASE

13 ANAPHASE

14 TELOPHASE

15

16 SKIN CELLS ARE CONSTANTLY DIVIDING

17 BREAST CELLS NORMAL CANCEROUS

18 COMPARISON OF MITOSIS AND MEIOSIS

19 MEIOSIS – MEIOSIS I

20 MEIOSIS – MEIOSIS II

21 DOWN’S SYNDROME

22 Characteristics of Down’s Syndrome 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: 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: Poor muscle tone Poor 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 hands Short, broad hands with a single crease across the palm on one or both hands Broad feet with short toes Broad feet with short toes Flat bridge of the nose Flat bridge of the nose Short, low-set ears Short, low-set ears Short neck Short neck Small head Small head Small oral cavity Small oral cavity Short, high-pitched cries in infancy. Short, high-pitched cries in infancy.

23 MATERNAL AGE vs. RATE OF DOWN’S SYNDROME

24 KARYOTYPING = a technique to visualize the chromosomes and number of chromosomes in a dividing cell

25 HUMAN FEMALE KARYOTYPE

26 HUMAN MALE KARYOTYPE

27 DOWN’S SYNDROME KARYOTYPE

28 COMPARISON OF MITOSIS AND MEIOSIS

29 NONDISJUNCTION = failure of chromosomes to separate during meiosis

30 FERTILIZATION AFTER NONDISJUNCTION IN AN EGG

31 Amniocentesis = sampling the amnionic fluid around the fetus for fetal cells

32 Chorionic Villi Sampling = sampling the placental cells which have the same DNA as fetal cells

33 KLINEFELTER’S SYNDROME (XXY) = due to nondisjunction of sex chromosomes Due to fertilization with an egg or sperm that has an extra X chromosome

34 TURNER’S SYNDROME (XO) = due to nondisjunction of sex chromosomes Due to fertilization with an egg or sperm lacking an X chromosome

35 Proteins Perform Most Cell Functions


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