HUMAN REPRODUCTION

Male Reproduction System

The purpose of the male reproductive system is to produce and deliver sperms. Sperm is the male gamete or sex cell. Sperm production is influenced by the hormone testosterone, which is produced in the testis.  Sperms are also produced in the testis. For further explanation.

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Female Reproductive System

The purpose of the female reproductive system is to produce eggs and provide a safe nutritious place for the embryo to develop. Egg maturation and release is influenced by the hormone estrogen, and estrogen is produced by the ovaries. The egg is the female sex cell. For further explanation.


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Second Link:  REPRODUCTIVE SYSTEM


Third Link:  REPRODUCTIVE SYSTEM

HUMAN REPRODUCTION

"CHECK OUT THIS VIDEO ON OVULATION AND FERTILIZATION"

Ovaries- produce eggs.


Ovulation- is the process where the ovary releases the egg.

Fallopian tubes- also known as oviduct is the site of fertilization or is where the sperm meets the egg.


Fertilization- is the union of sperm and egg.


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After the sperm enters the egg, the newly formed cell or the zygote travels to the uterus for implantation.

Zygote- is a fertilized egg
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Uterus- is a structure in the female reproductive system that provides a safe nutritious environment for the embryo or fetus to develop.


Placenta- is the site of exchange between the fetus and the mother. For example, nutrients and oxygen go from the mother to the fetus and waste products and CO2 go from the fetus to the mother.


Sexual reproduction requires two parents and the offspring are not identical, except in the case of identical twins.


Asexual reproduction requires only one parent and the offspring are genetically identical to the parent. ( binary fission, fragmentation and budding are other types of asexual reproduction and cloning.

How are sex cells different from body cells?

• sex cells have half the number of chromosomes, while body cells have a full set of chromosomes.

What type of cell division produce sex cells?

• meiosis produces the sex cells or gametes (the sperms or the eggs).

In what structure in the female reproductive system does fertilization occur?

• Fertilization occurs in the fallopian tube or oviduct. Fertilization is when the sperm enters the egg.

List two substances that can harm a developing fetus.

• Two substances that can harm fetus are drugs and alcohol.

What is the role of the placenta?

The placenta allows material to be exchanged between the fetus and the mother. For example: oxygen goes from the mother to the baby, while carbon dioxide goes from the baby to the mother

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Quiz Yourself

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Genetic Engineering/DNA technology

Genetic Engineering 
involves removing a gene from one organism or living thing and placing it into another organism. This is done so that the organisms with the new gene can make the gene's product. For example, a human insulin gene can be removed from a human chromosome and then inserted or placed into bacteria, and now because the bacteria has the gene for insulin, the bacteria can make insulin.  

The bacteria do not use insulin, they pass it out as waste product and humans extract or collect the insulin and use it for people who suffers with diabetes.

Remember, a gene is information on how to make a protein. Once the organism has the gene, it can make the protein.


 Transgenic organisms
are organisms with functional foreign genes.

If you place a human gene into bacteria, then the bacteria will make a human protein.

A gene is information on how to make a protein.

Click here to view GENETIC ENGINEERING ANIMATION
Questions and Answers

Identify two molecules that can be made using genetic engineering

• Insulin and growth hormone

 List two ways that people benefit from genetic engineering.

• People who are diabetic can now take insulin that is produced through genetic engineering and also, youngsters who are not producing growth hormones are able to take growth hormones produced by this technique.

What role does insulin play in the body?

• Insulin lowers blood sugar level (It does this by converting glucose into a storage form called glycogen and glycogen is stored in the liver.)

What organ or endocrine gland produces insulin?

• Insulin is produced by the pancreas.

Another hormone called glucagon is antagonistic or works to reverse the action of insulin by raising blood sugar level. (Glucagon converts glycogen back into glucose and the glucose is release into the blood.)

Restriction Enzymes

are bacteria enzymes that cut double stranded DNA at a specific locations called restriction sites. These restriction sites are found on the non-coding regions of the DNA sometimes referred to as junk DNA . The locations of the restriction sites are different for different individuals. Because we inherit our DNA and therefore our restriction sites from our parents, when using the same restriction enzymes, the cuts are made at similar locations for people who are closely related.

Animation of Restriction Enzymes


NOTE: In order to remove a human gene from the human chromosome, it is necessary to cut the gene out of the chromosome and this is done using a restriction enzyme.

ADDITIONALLY: In order to place a human gene into bacteria, it is also necessary to cut the bacteria's DNA using the same restriction enzyme that was used to cut the human gene. Another enzyme called ligase is used to join or splice the human gene to the bacteria's DNA.

RESTRICTION ENZYMES are the cutting tools in genetics.

IN FORENSIC ANALYSIS: In forensic analysis/crime scene investigation, restriction enzymes are used in conjunction or together with another technique called "gel electrophoresis".

Treating DNA with restriction enzymes results in fragments or pieces of different sizes.

GEL ELECTROPHORESIS is method that is used to separate molecules based on their sizes and charges. This technique creates a banding pattern or stains based on the size of the fragments or pieces in the sample used.  This technique is used in forensic analysis to include or exclude a person as a potential suspect.  It is used to establish identification.  Additionally, it is used to determine relationship.  For example, it is used to determine paternity.

GEL ELECTROPHORESIS LAB 1

Gel Electrophoresis Virtual Lab

People who are closely related, their DNA will create similar banding pattern on the gel electrophoresis. This is because the pieces that are generated by the enzyme are of similar sizes.

ONLINE CRIME SCENE INVESTIGATION

Designer Babies Video

Discovery Channel Human Cloning Video

 

 

Check this cloning interactive

OTHER METHODS THAT ARE USED AS MOLECULAR EVIDENCE TO DETERMINE RELATIONSHIP ARE:

• Enzyme test

• Paper chromatography is a technique used to separate pigment into individual colors.

• Amino acid sequence
• DNA sequence

Questions

• List two ways that we benefit from genetic engineering
• What is gel electrophoresis?
• In the Biodiversity Lab, what laboratory tools are used in place of restriction enzymes?
• What is the purpose of placing a human gene into bacteria?

Answers

• We benefit in medicine and in agriculture.
• Gel electrophoresis is a technique used to separate molecules by size.
• In the biodiversity lab, scissors are used in placed of restriction enzymes.
• We place human gene into bacteria so bacteria can make human protein.

List one genetic disease.
• Sickle cell


Identify a technique, which can be used to diagnose this disease
• Gel electrophoresis


List one chromosomal disease.
• Down syndrome


Identify a technique, which can be used to diagnose this disease
• Karyotype


CLICK HERE TO SEE ANIMATION OF KARYOTYPE

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The Systems and Homeostasis

HOMEOSTASIS is defined as all the processes that help maintain an organism internal environment.

How does the digestive system help in maintaining homeostasis?

The digestive system breaks down food into a form that the cells can use to maintain homeostasis. (Just like in the diffusion lab, the starch was too big and could not go through the artificial membrane. If the food is too big, it will not be able to enter the cell. It will not fit in the holes in the cell membrane)

Digestion begins in the mouth. In the mouth, mechanical digestion starts with the teeth grinding food into smaller pieces. The salivary glands releases saliva, which has a digestive enzyme called amylase. Amylase breaks down starch into smaller pieces and also produce a new substance. Additionally, the saliva moistened the food while the tongue rolls it into a ball. Once the the food is push back to the pharyngeal area, swallowing is initialized automatically.

How would you feel if you were not able to digest your food?

CHECK OUT SOME OF THE ORGANS OF THE DIGESTIVE SYSTEM!

WATCH THIS VIDEO OF THE DIGESTIVE SYSTEM!

ENZYMES AT WORK

ENVIRONMENTAL FACTORS ON ENZYME ACTIVITIES

pH AND ENZYME FUNCTION

How does the respiratory system help in maintaining homeostasis?

- The respiratory system takes in oxygen needed to make ATP and removes carbon dioxide. These activities are necessary in order to maintain homeostasis.

The Human Respiratory System

CHECK THESE VIDEOS ON THE RESPIRATORY SYST. "RESPIRATORY SYSTEM"

How does the circulatory system help in maintaining homeostasis?

- The circulatory system carries oxygen, nutrients and other needed molecules to the cells, while carrying away waste product from the cells.


CHECK THESE VIDEOS ON THE CIRCULATORY SYSTEM: "CIRCULATORY SYSTEM"

How does the immune system help in maintaining homeostasis?

- The immune system is involved in destroying foreign particles and pathogens that would disrupt homeostasis. The immune system kills bacteria and viruses.

How does the endocrine system help in maintaining homeostasis?

- The endocrine system helps maintain homeostasis through the actions of its chemical messengers called hormones. Hormones interact with specific receptors found on cell surfaces or inside the cell. Hormones are produced in specialized cells called endocrine glands and they are released into the blood. The pancreas is an endocrine gland and it produces insulin and glucagon. Insulin lowers blood glucose level by converting glucose into a storage form called glycogen and glycogen is stored in the liver. Glucagon raises blood sugar level by converting glycogen back into glucose.



HORMONES AND RECEPTORS VIDEO

CHECK OUT THIS INTERACTIVE

"CONTROLLING BLOOD SUGAR LEVELS"

Check Out This Video "Endocrine System"

How does the nervous system help to maintain homeostasis?

- The nervous system controls homeostasis using nerve impulses or electrical signals.

How does the excretory system help to maintain homeostasis?

- The excretory system is a series of systems involved in removing waste from the body. For example: the digestive system removes solid waste from the body; the urinary system removes liquid waste from the body; the respiratory system removes carbon dioxide and water from the body; the skin removes nitrogenous waste and other dissolved waste substances.

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IMMNUNE SYSTEM

The purpose of the immune system is protect the body from pathogens or any foreign particles that can disrupt homeostasis.


What are some ways your body can react when it is invaded by pathogens?

Some possible immune reactions that can occur when your body is invaded by pathogens or foreign particles are:

- produces mucus to trap the pathogens.

- sneezing and coughing to uproot and excrete the pathogens.

- fever to increase blood flow.

- produces white blood cells.

- produces antibodies against invading pathogens.

What are pathogens?

• Pathogens are disease causing organisms. Ex. bacteria, viruses.

What are antigens?

• Antigens are any foreign particle in the body that triggers an immune reaction.

What are antibodies?

• Antibodies are special proteins that are made by your white blood cells to fight infections.

Note: Antibodies are proteins, that is they have specific shape. Antibodies that work against one pathogenic organism will not work against another because of the shape difference.

What are antibiotics?

• Antibiotics are drugs that fight pathogens (bacteria, viruses).

What are vaccines?

• Vaccines are a weakened form of a disease used to stimulate the production of antibodies against the disease.

CELL DIVISION

Why do cells divide?

• Growth
• Repair
• Old cells die
  

Mitosis is a cell division that produces two daughter cells that are identical in chromosome number and in combination, for example, a cell with 23 pairs of chromosomes will yield two daughter cells each with 23 pairs of chromosomes and have the same combination.

Cancer is uncontrollable mitosis. The cells continue to divide nonstop and are immortal.

• Meiosis is a cell division that produces the gametes or sex cells.
  
• Meiosis reduces the number of chromosomes in half. For example, if a cell has 46 chromosomes and it undergoes meiosis, it will make four daughter cells with 23 chromosomes each. Each of the cells produced by meiosis have a different combination.
  

When the cell is dividing, if it is producing a sperm or an egg it is meiosis, if not, mitosis.

Meiosis only occurs in the testis and the ovaries.

Fertilization is the union of the sperm and the egg. This union occurs in the fallopian tube

Fertilization restores the chromosome number of the organism.

Meiosis and fertilization are responsible for the variations in species.

Zygote is a fertilized egg.

After the zygote is formed, the cell divides by mitosis and differentiates into the new structures of the organism.

Note: The advantage of sexual reproduction is variation.

Questions

• What is mitosis?
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• How are cell produced by mitosis different from cells produced by meiosis?
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• Explain fertilization.
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• Where does fertilization take place?
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• What is the significance of fertilization?
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• What are zygotes?
  

• In what structures of the male/female reproductive system does meiosis occur?

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