3.1.5 Sexual Reproduction in Humans

Question 1

What is the Role of the Penis in the Male reproductive system?

Answer 1

Passes urine out of the body from the bladder and allows semen (sperm) to pass into the vagina of a woman during sexual intercourse.

Question 2

What is the Role of the Testis in the Male reproductive system?

Answer 2

Contained in a bag of skin (Scrotum) and produces sperm and testosterone (hormone)

Question 3

What is the Role of the Scrotum in the Male reproductive system?

Answer 3

Sac supporting the testes outside the body to ensure sperm at a temperature slightly lower than body temperature.

Question 4

What is the Role of the Urethra in the Male reproductive system?

Answer 4

A tube running down the center of the penis that can carry out sperm or urine, a ring in the Urethra prevents the sperm and urine from mixing.

Question 5

What is the Role of the Prostate Gland in the Male reproductive system?

Answer 5

Produces fluid called semen that provides sperm cells with nutrients.

Question 6

What is the Role of the Sperm Duct in the Male reproductive system?

Answer 6

Sperm passes through the sperm duct to be mixed with fluids produced by the glands before being passed into the urethra for ejaculation.

Question 7

What is the Role of the Oviduct in the female reproductive system?

Answer 7

Connects the ovary to the uterus and is lined with ciliated cells to push the released ovum down it. Fertilization occurs here

Question 8

What is the Role of Ovary in the female reproductive system?

Answer 8

Contains Ova (Female Gamete) which will mature and develop when hormones are released.

Question 9

What is the Role of the Uterus in the female reproductive system?

Answer 9

Muscular bag with a soft lining where the fertilized egg (Zygote) will be implanted to develop into a fetus

Question 10

What is the Role of the Vagina in the female reproductive system?

Answer 10

A muscular tube that leads into the inside of a woman’s body, where the male penis will enter during sexual intercourse and where sperm are deposited

Question 11

What is the Role of the Cervix in the female reproductive system?

Answer 11

Ring of muscle at the lower end of the uterus to keep developing fetus in place during pregnancy

Question 12

A gamete is a :

Answer 12

Sex cell, in animals: sperm and ovum; in plants pollen nucleus and ovum

Question 13

Why do gametes differ from normal cells?

Answer 13

Gametes differ from normal cells as they contain half the number of chromosomes (23) found in other body cells (46). This is because they only contain one copy of each chromosome, rather than the two copies found in other body cells

Question 14

In human beings, a normal body cell contains how many chromosomes

Answer 14

46 chromosomes

Question 15

How many chromosomes are in each gamete

Answer 15

each gamete contains 23 chromosomes

Question 16

Name all the 4 structures of a sperm cell

Answer 16

#1. Flagellum (tail) 
#2. Haploid Nucleus 
#3. Acrosome 
#4. Midpiece containing Mitochondria

Question 17

What is a Haploid Nucleus

Answer 17

A cell nucleus with half the normal number of chromosomes (sperm and ova)

Question 18

Name all the 4 structures of an egg cell

Answer 18

#1. Cell Membrane 
#2. Cytoplasm 
#3. Haploid Nucleus 
#4. Mitochondria

Question 19

(Adaptive Features Sperm) has a flagellum:

Answer 19

Reason: The flagellum enables the sperm cell to swim to the egg.

Question 20

(Adaptive Features Sperm) Contains enzymes in the head region (Acrosome)

Answer 20

Reason: To digest through the jelly coat and cell membrane of an egg cell when it meets one.

Question 21

(Adaptive Features Sperm) Contains many mitochondria

Answer 21

Reason: Provides energy from respiration so that the flagellum can move back and forth for locomotion.

Question 22

(Adaptive Features Egg) Cytoplasm containing a store of energy

Answer 22

Reason: Provides energy for dividing the zygote (fertilized egg) after fertilization

Question 23

(Adaptive Features Egg) Jelly like coating that changes after fertilization

Answer 23

Reason: Forms an impenetrable barrier after fertilization to prevent other sperm nuclei from entering the egg cell.

Question 24

What is the size of the Sperm and Egg Cell

Answer 24

Sperm: 45 Micrometers
Egg: 0.2 Millimeters

Question 25

What is the Description of the structure of the Sperm and Egg Cell

Answer 25

Sperm: Head Region and Flagellum, many structural adaptations.

Egg: Round cell with few structural adaptations covered in a jelly coating

Question 26

What is the movement of the Sperm and Egg Cell

Answer 26

Sperm: Capable of Locomotion

Egg: Not capable of Locomotion

Question 27

What are the production numbers of the Sperm and Egg Cell

Answer 27

Sperm: Produced every day, around 100 million per day.

Egg: Thousands of immature eggs in each ovary, but only one is released each month.

Question 28

During ejaculation in the male, millions of sperm cells move along the sperm duct, also known as the:

Answer 28

vas deferens

Question 29

The sperm are suspended in:

Answer 29

Semen, a fluid secreted by the prostate gland

Question 30

The semen passes into the:

Answer 30

urethra

Question 31

Describe the entire process of fertilization.

Answer 31

1. During sexual intercourse, semen is ejaculated into the vagina of the female, near the cervix

#4. If a sperm cell meets an egg cell in the oviduct, fertilization can occur
- This is most likely to occur 1-2 days after the female has ovulated (released an egg cell from one of her ovaries into an oviduct)

Question 32

Fertilization is the fusion of the nuclei from:

Answer 32

A male gamete (Sperm) and a Female Gamete (Egg Cell)

Question 33

During fertilization, the head of a sperm cell releases enzymes, why?

Answer 33

To digest a path through the protective outer layer of the egg cell, allowing the sperm to pass through the egg cell membrane.

Once this occurs, the egg cell immediately releases a thick layer of material that prevents any more sperm cells from entering, ensuring only one sperm cell can fertilize the egg cell

Question 34

When the male and female gametes fuse, what do they become?

Answer 34

A zygote (fertilized egg cell)

Question 35

How many chromosomes does a zygote contain

Answer 35

This zygote contains the full 46 chromosomes

Question 36

The zygote divides by mitosis to form two new cells, which then continue to divide like this until, what?

Answer 36

An embryo (early stage of development) is formed after a few days.