PBS-NOVA: Life's Greatest Miracle Flashcards

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Questions and Answers

How many human babies are born each day?

365,000

What is DNA 'very good' at?

making copies of itself

What risk is there for a species that only reproduces by cloning?

If one person has a weak immune system, one successful parasite could wipe us all out

How does the DNA of sexually produced offspring compare to the DNA of the parents?

It is half and half/split Signup and view all the answers

How many sperm are produced by the average human male?

200 million Signup and view all the answers

What process is used to make sperm cells and egg cells?

meiosis Signup and view all the answers

What happens to the genes when two chromosomes 'embrace'?

They exchange DNA Signup and view all the answers

What is the advantage of diversity within a species?

Better odds that someone will create a new species Signup and view all the answers

When does a human female produce her eggs?

when she is a fetus Signup and view all the answers

What danger confronts sperm in the vagina?

It is acidic Signup and view all the answers

What does the sperm need to be allowed through the egg's zona?

must break through the egg's zona, proteins need to match up Signup and view all the answers

How much time passes between fertilization and the first division of the zygote?

24 hours Signup and view all the answers

After fertilization, how long does it take for the blastocyst to arrive in the uterus?

5 days Signup and view all the answers

What risk does the blastocyst face after it attaches to the uterus?

could be attacked by mother's immune system Signup and view all the answers

True or False: All cells have the same genes

False Signup and view all the answers

What does a gene do when it has been turned on?

something has to come in and loosen some DNA to turn genes on Signup and view all the answers

Where specifically does the baby get its nutrients from?

placenta Signup and view all the answers

Does the blood of the mother and the baby ever mix?

False Signup and view all the answers

How old is the fetus when it gains the ability to hear sound?

5 months Signup and view all the answers

What is the main job of the fetus during the last trimester?

to grow Signup and view all the answers

Study Notes

Reproduction and Development

365,000 human babies are born each day, indicating high reproductive rates globally.
DNA is highly efficient at self-replication, ensuring genetic information is preserved across generations.
Cloning as a reproduction method poses risks; a single pathogen could devastate a species with shared weak immune systems.
Offspring from sexual reproduction inherit an equal contribution of DNA (50%) from each parent.
An average male produces around 200 million sperm, highlighting the competition for fertilization.
Gametes (sperm and egg cells) are produced through the process of meiosis.

Genetic Exchange and Diversity

Chromosomes can exchange DNA when they pair, increasing genetic variation.
Genetic diversity within a species improves adaptability and survival, raising chances of speciation.
Females produce their eggs while still in the fetal stage, emphasizing early developmental processes.

Fertilization and Early Embryonic Development

Sperm encounters an acidic environment in the vagina, presenting a challenge for successful fertilization.
For sperm to penetrate the egg's zona, specific protein matches are necessary, demonstrating biochemical compatibility.
Approximately 24 hours elapse from fertilization to the first division of the zygote, marking the start of cell division.
The blastocyst takes about 5 days to reach the uterus after fertilization, essential for implantation.
Once implanted, the blastocyst may face immune rejection from the mother's body, posing a risk to development.

Genetics and Nutrition During Pregnancy

Not all cells in an organism contain identical genetic material; different types of cells express specific genes.
Gene activation involves loosening DNA, indicating that certain environmental factors play a role in gene expression.
The placenta serves as the primary source of nutrients for the developing fetus.
There is no mixing of blood between the mother and the fetus, ensuring a separate circulatory system.

Fetal Growth and Sensory Development

A fetus develops the ability to hear sounds at around 5 months gestation, indicating advancements in sensory development.
The primary task of the fetus during the last trimester is growth, preparing for birth and life outside the womb.

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Description

Test your knowledge on key concepts from the PBS-NOVA documentary 'Life's Greatest Miracle'. These flashcards cover topics such as human reproduction, DNA functions, and the implications of cloning in species. Perfect for students and biology enthusiasts alike!