Life's Greatest Miracle

Question 1

How many babies get made around the world every day?

Answer 1

About 365,000

Question 2

From a single cell, you build a body that has how many cells?

Answer 2

100 trillion

Question 3

How many new sperm does the average man churn out every second, day, and over a lifetime?

Answer 3

1,000; 100 million; > 2 trillion

Question 4

How are sperm and egg cells made?

Answer 4

Meiosis

Question 5

In almost every cell in our body, how many different genes do we have spread out on chromosomes?

Answer 5

30,000

Question 6

When is the only time that the 23 chromosomes from each parent come together?

Answer 6

Meiosis

Question 7

What is the process of mitosis?

Answer 7

1) Each chromosome makes an exact copy of itself keeping it attached at one point
2) Condense creating an X-shape
3) Chromosome partners come together and cling so closely that big chunks carrying whole branches of genes get exchanged between them
4) Cell divides twice, each time pulling the pairs apart
5) Results in sperm or egg with 23 chromosomes

Question 8

When do women create several million eggs?

Answer 8

Within a couple months of being a fetus in the whom

Question 9

What happens to an immature egg cell every month?

Answer 9

1) Woman’s two ovaries selects an immature egg cell
2) Egg and support cells ooze out of the ovary
3) Goes through the fallopian tube into the uterus where tentacles capture the egg and pull it inside
4) Egg is swept along by muscular contractions of the tube as well as the constant swaying of tiny cilia

Question 10

Why must a prepared egg be fertilized within a few hours?

Answer 10

It will die

Question 11

How does sperm get into the vagina?

Answer 11

1) Hormones cue blood vessels to relax allowing spongy tissue in the penis to fill with blood
2) At the height of sexual excitement, millions of sperm are squeezed out of storage and swept up by fluid gushing from several glands including the prostate
3) The flood carries them into a 15-inch long tube looping into the abdomen and then out through the penis

Question 12

What is the sperm’s first obstacle?

Answer 12

The cervix (passageway to the uterus) - Most of the time, it’s locked out and plugged with mucus that keeps bacteria and sperm out, but just a few days a month around ovulation, the mucus becomes watery and forms tiny channels that guide the sperm through

Question 13

What propels the sperm into the fallopian tube?

Answer 13

Undulations of the uterine muscles

Question 14

What sperm may have a better chance at joining with the egg?

Answer 14

The ones caught up in the cilia lining of the tube

Question 15

Further up the fallopian tube the sperm will find the egg heavily chaperoned by what?

Answer 15

Support cells

Question 16

What is the egg itself encased in?

Answer 16

A think protein shell called the zona

Question 17

What must the sperm do to fertilize the egg?

Answer 17

Break through the zona by using proteins that protrude from the sperms cap to hoop up with precise set of proteins on the eggs surface, and if they match, the sperm is held fast and undergoes a dramatic transformation. It sheds its outer coating, releasing powerful enzymes that dissolve a hole in the zona allowing the sperm to push its way through. The membranes of the two cells fuse and the egg draws the entire contents of the sperm inside

Question 18

How many fertilized eggs fail to develop?

Answer 18

Over 50%

Question 19

In order for a fertilized cell to survive, what must it do?

Answer 19

• Order the zona to lock out all other sperm
• Finish meiosis, expelling half of its chromosomes into a tiny pouch called a polar body

Question 20

Since the sperm entered the egg, how much time has passed and what has the fertilized egg been doing?

Answer 20

24 hours; moving down the fallopian tube toward the uterus

Question 21

Why do the cells divide every few hours?

Answer 21

To create the building blocks needed to construct an embryo

Question 22

How many days after fertilization does the egg arrive in the uterus?

Answer 22

5

Question 23

What must the now called blastocyst do?

Answer 23

Break out of the zona and find a source of nourishment

Question 24

At the beginning of the 6th day, how does the blastocyst orchestrate an escape?

Answer 24

Releases an enzyme that eats through the zona and the ball of cells squeezes it out onto the blood-rich lining of the uterus

Question 25

What might happen now that the blastocyst has been striped of its protective coating?

Answer 25

Could be seen as a foreign invader and attacked by the mother’s immune system - white blood cells could swarm to devour it

Question 26

How does the striped blastocyst try and prevent being seen as a foreign invader?

Answer 26

Produces several chemicals that suppress the mother’s immune system so that it is free to search for food and oxygen

Question 27

What is gastrulation?

Answer 27

The process in which cells start to organize themselves into an embryo

Question 28

Where does gastrulation occur?

Answer 28

Mother’s uterine lining

Question 29

What occurs during gastulation?

Answer 29

1) Blastocyst creates 2 oblong bubbles one on top of the other with a thin layers of cells between them
2) Some cells begin moving toward the centre, then they dive downwards, creating a new lower level
3) More cells plunge through squeezing in between to form a third level

Question 30

What is the lower level destined to form?

Answer 30

Structures like the lungs, liver, and the lining for the digestive tract

Question 31

What will the middle layer form?

Answer 31

Heart, muscles, bones, and blood

Question 32

What will the top layer create?

Answer 32

The nervous system, including the spinal cord and the brain, as well as an outer covering of skin, and eventually hair

Question 33

How long is a human embryo 3 weeks after fertilization? What is happening during this time?

Answer 33

Less than a tenth of an inch; Beginning of the nervous system is in place, primitive brain cells exposed, cells multiplying, forming blood vessels, heart begins to beat

Question 34

How long is a human embryo 4 weeks after fertilization? What is happening during this time?

Answer 34

A fifth of an inch; primitive backbone curls into a tail which will disappear in a few weeks, large brain and eyes develops

Question 35

How do different cells do different jobs in different areas of the body?

Answer 35

Each cell has different groups of genes that are turned on or off when constructing a particular protein

Question 36

What is collagen?

Answer 36

A fiber that makes up much of your skin, tendons, and bones

Question 37

What is crystallin?

Answer 37

A protein that helps make the lens of your eye clear

Question 38

What proteins move muscle fibers?

Answer 38

Actin and myosin

Question 39

What does hemoglobin do?

Answer 39

Carries oxygen from the lungs to the rest of the body

Question 40

How does a cell turn on the right set of genes to create the right protein?

Answer 40

Part of the answer seems to be location. Chemicals in one cell can trigger a reaction in the cell next door that can spread to the cell’s nucleus and turn genes on or off.