Week 6: Questions

Question 1

What is the difference between a body and a person?

Answer 1

A body is what develops and grows (embryo, fetus, baby) and a person is one who carries out the life of this body

Question 2

How are cells the basic unit of life?

Answer 2

They compose everything (organs, blood, tissues, fibers) that are used to make up the human body

Question 3

Cell membrane

Answer 3

Outer boundary of the cell body, where the cell encounters its environment

Detect chemicals from other cells

Start communication between a human egg and sperm cell

Stick to other cells to make multicellular structures (ex. Tissues and organs)

Question 4

Cytostol

Answer 4

A substance where small molecules are dissolved and organelles are implanted

In cell membrane

Question 5

Cytoplasm

Answer 5

Cytosol and organelles together

In cell membrane

Question 6

Nucleus

Answer 6

The most prominent organelle in the cell

Houses the chromosomes

Question 7

Chromosome

Answer 7

Structure that contains most of the genetic information of the cell

In nucleus

Question 8

Mitochondrian

Answer 8

Organelle responsible for extracting energy from mood molecules

Question 9

Endomembrane System

Answer 9

Produces important molecules and delivers them to key locations inside and outside of the cell

Collects, packages and removes waste materials (that would otherwise lead to improper brain development and other defects)

Question 10

Endoplasmic Reticulum

Answer 10

A series of membrane folds located near the nucleus

In endomembrane system

Smooth ER: handles synthesis of fats and lipids, breaks down and eliminates some toxic substances

Rough ER: produces proteins

Question 11

Ribosome

Answer 11

Studs the surface of rough ER and threads the protein into the interior of the rough ER while it’s being formed

In endomembrane system

Question 12

Golgi Apparatus

Answer 12

Place where many proteins acquire their final structure

Vesicles leave here to travel to cell membrane and release their content to the space outside the cell

In endomembrane system

Question 13

Lysosome

Answer 13

Digests waste materials and worn out organelles

Recycles molecules so they can be reused

In endomembrane system

Question 14

Cytoskeleton

Answer 14

Maintains the shape of the cell and positions of the organelles

Microtubules: hollow rods that determine cell shape and help with cell movement

Microfilaments: thin, strong and versatile and also help in cell movement

Intermediate filaments: strengthen cells and areas of the embryo

Question 15

What type of cell has organelles (a human cell is one of these)?

Answer 15

Eukaryotic cells

Question 16

Which part of a cell maintains its shape and allows it to move?

Answer 16

Cytoskeleton→ microtubules

Question 17

Parkinson’s Disease is associated with the build up of a specific protein) in the nerve cells that prevents the movement of other proteins from the endoplasmic reticulum (ER) to the Golgi apparatus. What do you think happens to a cell when protein transfer between the ER and the Golgi apparatus is stopped?

Answer 17

The protein cannot reach its final stage/structure

Question 18

Interphase

Answer 18

cells work to prepare materials that will be necessary for meiosis to occur. Chromosomes replicate, organelles continue to function, cell increases in size and chromosomes are loosely packaged

Question 19

Prophase 1

Answer 19

chromosomes become shorter and thicker and line up with their homologues. The membrane surrounding the nucleus comes apart, leaving the chromosomes in the cytoplasm. During this stage in the rest of the cell, a spindle (helps to distribute chromosomes to new cells) is being formed

Question 20

Metaphase 1

Answer 20

specific proteins associated with the fibres of the mitotic spindle pull the chromosome toward both poles, which results in the pair of chromosomes lining up in a single file down the middle of the cell

Question 21

Anaphase 1

Answer 21

the paired chromosomes separate and move to opposite poles (using shrinking microtubules to move). This results in a haploid set of chromosomes on each side of the cell, which is the end of meiosis 1. However, meiosis is not over yet because currently each chromosome is composed of two identical chromatids, which need to be separated

Question 22

Prophase 2

Answer 22

the chromosomes (still in their compact form) attach to a newly formed spindle

Question 23

Metaphase 2

Answer 23

chromosomes are captured by one or more microtubules from each side and line up in single file in the middle of the cell

Question 24

Anaphase 2

Answer 24

the two chromatids of each chromosome detach from each other and move to opposite ends of the cell. Each half of the cell has a complete haploid set of chromosomes and each chromosome is composed of a single chromatid

Question 25

Telophase 2

Answer 25

the nuclear membrane reforms which encloses the chromosomes. The chromosomes return to their recondensed form

Question 26

Cytokenesis

Answer 26

pinches the cells in two

The final product is four haploid cells

Question 27

Why is it important that gametes be haploid?

Answer 27

Because then they only have half the number of chromosomes, which is important because they will be combing with another gamete to get the other half

Question 28

What is a homologous pair of chromosomes? Why is it important?

Answer 28

A set of one maternal and one paternal chromosome that pair up inside a cell during fertilization
Because they allow for genetic recombination and separation of genetic material from the mother and father into new cells

Question 29

Why do you think that the chromosomes are moved to the centre of the cell in metaphase I before they are separated in anaphase I?

Answer 29

So that they can divide into two equal cells

Question 30

Describe one difference in the results of this experiment that would have occurred if Lazzaro Spallanzani had chosen to put the pants on the female frogs instead of the male frogs

Answer 30

He would not have been able to collect the semen to combine it with frog eggs, and therefore would not have seen the fertilization take place

Question 31

What is the fate of the majority of the sperm during fertilization?

Answer 31

Most do not make it all the way to through the fertilization process because there are numerous processes to get through

Question 32

What is the difference in the number of chromosomes in the cells at the end of mitosis and at the end of meiosis II?

Answer 32

In mitosis it is 23, in meiosis it is 46

Question 33

All diploid cells in an organism contain the same DNA or genetic material. True or False?

Answer 33

True, but only the genes necessary for a given cell to do its particular “job” are expressed

Question 34

How does a stem cell become a heart muscle cell, and once it does, can it change to another type of cell?

Answer 34

This happens through differentiation, which means that as the cell specializes, it will take on a specific structure and function and result in a heart muscle
It cannot change to another cell once it has specialized

Question 35

List three differences between mitosis and meiosis

Answer 35

Meiosis
Ends with 4 haploid cells
Has 2 rounds of cell division
Each cell has 46 chromosomes

Mitosis
Ends with 2 diploid cells
Has 1 round of cell division
Each cell has 23 chromosomes

Question 36

Three types of cells in gastrulation

Answer 36

Not yet specialized and only give rise to certain cells
Ectoderm
Mesoderm
Endoderm

Question 37

Do fraternal twins share more identical genes than siblings that are not twins?

Answer 37

No because this is a result of two eggs being fertizled by two sperm cells

Question 38

The Hensel twins have stated in interviews that they want their lives to be normal - date, get married and have children. Now that you know more about conjoined twins, if Abigail and Brittany do have a child, should both or only one of them be listed as the mother on the child’s birth certificate? Explain your answer.

Answer 38

Only one of them because although they share the same body, they are separate people so only one of them would be the mother

Question 39

Scientists can’t induce twinning in humans to learn how it works because that would be unethical. What do they do instead?

Answer 39

They run experiments on other organisms