Science Test review if u fail ill kill you

Question 1

Describe the main points of the cell theory.

Answer 1

The cell theory states that All living things are made up of cells. The cell is the simplest unit that can carry out all life processes. All cells are reproduced from other cells.

Question 2

Compare prokaryotes and eukaryotes, and give an example of each.

Answer 2

The simplest life forms are called prokaryotes. These single-celled life forms have no nucleus. A bacterium is an example of a prokaryote.

More complex organisms are called eukaryotes. Eukaryotes may be single-celled or multi-celled organisms with a nucleus. Plants and animals are examples of eukaryotes.

Question 3

Cell Membrane

Answer 3

the semipermeable membrane surrounding the cytoplasm of a cell.

Question 4

Cytoplasm

Answer 4

The fluid inside a cell but outside the cell’s nucleus, Most chemical reactions inside a cell are here

Question 5

Nucleus

Answer 5

The nucleus controls and regulates the activities of the cell and carries the genes, structures that contain the hereditary

Question 6

Mitochondria

Answer 6

Mitochondria are membrane-bound cell organelles that generate most of the chemical energy needed to power the cell’s biochemical reactions

Question 7

Endoplasmic Reticulum

Answer 7

The endoplasmic reticulum (ER) is a large, dynamic structure that serves many roles in the cell including calcium storage, protein synthesis and lipid metabolism.

Question 8

Golgi Bodies

Answer 8

functions as a factory in which proteins received from the ER are further processed and sorted for transport to their eventual destinations

Question 9

Vacuoles

Answer 9

membrane-bound cell organelle. In animal cells, vacuoles are generally small and help sequester waste products. In plant cells, vacuoles help maintain water balance.

Question 10

Cell wall

Answer 10

A cell wall is defined as a rigid, external layer that is specifically designed to provide structural support and rigidity

Question 11

Chloroplasts

Answer 11

plant cell organelles that convert light energy into relatively stable chemical energy via the photosynthetic process.

Question 12

What are the main structural differences between plant and animal cells?

Answer 12

Animal cells each have a centrosome and lysosomes, whereas plant cells do not. Plant cells have a cell wall, chloroplasts and other specialized plastids, and a large central vacuole, whereas animal cells do not

Question 13

How do cells get their energy? What is the chemical reaction called that produces energy for the cell?

Answer 13

Through the process of cellular respiration, the energy in food is converted into energy that can be used by the body’s cells. During cellular respiration, glucose and oxygen are converted into carbon dioxide and water, and the energy is transferred to ATP.

Question 14

If the objective lens is at 4x, what is the actual magnification of the image being viewed?

Answer 14

40x

Question 15

What are the three main reasons cell division is so important?

Answer 15

Cells divide in order for organisms to reproduce, grow, and repair damage.

Plant and animal cells need energy, nutrients, water, and gases to live. Water is important because chemicals that enter the cells need to be dissolved in water to be used in chemical reactions within the cell.

Chemicals used for cell activity and growth enter the cell through the membrane and travel to where they are needed. This movement is called diffusion.

Water enters and leaves the cell in a process called osmosis.

Question 16

Briefly compare asexual and sexual reproduction.

Answer 16

When single-cell organisms divide and only one parent is involved, it is called asexual reproduction. The offspring is an exact genetic copy of the parent.

When multicellular organisms divide and two parents are involved, it is called sexual reproduction. The cell from one parent joins with the cell from another parent, and the offspring inherits characteristics from both parents.

Question 17

Briefly compare diffusion and osmosis.

Answer 17

In diffusion, particles move from an area of higher concentration to one of lower concentration until equilibrium is reached. In osmosis, a semipermeable membrane is present, so only the solvent molecules are free to move to equalize concentration.

Question 18

Why do cells divide instead of simply getting larger and larger?

Answer 18

So if a cell grows larger instead of dividing, diffusion will be too slow and the cell will not be able to obtain nutrients and get rid of wastes efficiently, which ultimately would kill the cell. Thus, cells divide so that an organism can get bigger, despite the fact that cell size is limited.

Question 19

The body cell of a horse has 64 chromosomes. How many chromosomes will new horse cells have after mitosis?

Answer 19

It would have 64 chromosomes. Before mitosis the genetic material of the cell is duplicated so that when the cell undergoes division the genetic material of the cell is equally divided and given to both of the daughter cells at the time of separation of the chromosomes that is the anaphase. After the cell division is over both the daughter cells will have the same number of chromosomes as that of the mother.

Question 20

What is typically the longest stage of the cell cycle?

Answer 20

Interphase

Question 21

What is the difference between a chromatid and a chromosome?

Answer 21

A chromatid is one of the two identical halves of a chromosome that has been replicated in preparation for cell division. The two “sister” chromatids are joined at a constricted region of the chromosome called the centromere.

Question 22

Interphase

Answer 22

Cells are usually in interphase, DNA is in extremely long, thin strands (not visible under microscope), Dna Strands Duplicate in preparation for cell division, organelles can also duplicate

Question 23

Mitosis

Answer 23

Division of the contents of the nucleus, occurs in four phases PMAT (prophase, metaphase, anaphase and telophase)

Question 24

Cytokinesis

Answer 24

division of everything else (cytoplasm, membrane, all organelles)

Question 25

Prophase

Answer 25

longstrands of DNA condense and become visible under microscope as chromosomes, each chromosome consists of two identical strands(chromatids) which are held today by a centromere, nucleus dissolves, contents spill into cytoplasm

Question 26

Metaphase

Answer 26

Chromosomes line up along middle of cell, microtubules attach to the centromere of each chromosome

Question 27

Anaphase

Answer 27

centromeres split and sister chromatids separate, chromatids are gradually pulled apart/moved around by specialized structures called spinal fibres

Question 28

Telophase

Answer 28

DNA strands back out, becoming invisible under microscope, new nucleus forms, cells appear to have two nuclei during this stage

Question 29

Why do you think cancer researchers are interested in studying the cell cycle “checkpoints”?

Answer 29

Cell cycle checkpoints are critical to prevent the cell from progressing to the next phase of the cell cycle before the prior phase has been completed and so by understanding the cell cycles “checkpoints” it can help researchers understand what went wrong and when.

Question 30

“Not all tumours are cancerous”. Explain this statement using proper terminology.

Answer 30

Tumors may be benign (not cancer) or malignant (cancer). Benign tumors may grow large but do not spread into, or invade, nearby tissues or other parts of the body. Malignant tumors can spread into, or invade, nearby tissues and so being “cancerous”

Question 31

Explain why early detection of cancer is so critical.

Answer 31

Early detection of cancer is so critical because the earlier the detection is the better the chances of successful treatment. By having an early detection you can act before the cancer spreads too much and also allows a more precise diagnosis and so better treatment.

Question 32

What are carcinogens? Describe two carcinogens that you think are most relevant to people of your age. What is the best way to avoid these carcinogens?

Answer 32

Carcinogens are environmental factors that cause cancer. 2 relevant examples are Alcohol and Tobacco as lots of people want to smoke and drink to seem older and more mature but are actually harming themselves. To avoid these carcinogens you should avoid peer pressure, avoid too many drinks, live tobacco free lifestyle, exercising reduces risk of cancer as well

Question 33

What are stem cells? Why are scientists interested in harvesting stem cells?

Answer 33

Stem cells are animal cells that can differentiate into many cell types. Scientists are interested interested in harvesting them because of the possibilities of repairing damaged cells and treating a wide range of diseases

Question 34

Compare embryonic stem cells and tissue stem cells in terms of versatility and controversy.

Answer 34

Embryonic stem cells can differentiate into any kind of cell. Tissue stem cells exist within specialized tissue and are only able to differentiate into certain types of cells

Question 35

Be able to briefly describe the function of each organ of the digestive system

Answer 35

The digestive tract is composed of the mouth that becomes the inlet of food. Digestion of carbohydrates starts in the mouth. Mechanical and chemical digestion occurs here with the teeth and amylase.
The chewed food is then swallowed. It travels through the esophagus to the stomach.
Food, especially proteins are digested in the stomach via proteases activated by HCI and muscular action of the stomach. The partially digested food is passed to the small intestines.
Food digested is finished in the first part of the small intestines. At the end of the small intestines, the digested food is absorbed into the bloodstream while the undigested matter is pushed into the large intestines.
Large intestines reabsorb excess water from the undigested matter as it travels to the anus.
The undigested matter is defecated out as stool via the anus.

Question 36

Why do we need a circulatory system?

Answer 36

The circulatory system carries oxygen, nutrients, and hormones to cells, and removes waste products, like carbon dioxide and without it carrying oxygen to the cells they would die and so we would die.

Question 37

What are the three main components of the circulatory system?

Answer 37

Heart, a muscular organ that pumps blood throughout your body.
Blood vessels, which include your arteries, veins and capillaries.
Blood, made up of red and white blood cells, plasma and platelets

Question 38

Describe the four main components of blood.

Answer 38

Red blood cells contain hemoglobin, which allows oxygen to be transported in the body
White blood cells fight infections in the blood
Platelets help blood clots
Plasma is a protein rich liquid that carries the blood cells

Question 39

How are arteries and veins different?

Answer 39

Arteries carry blood away from the heart, and veins carry blood towards the heart.

Question 40

What is the function of capillaries?

Answer 40

Capillaries are delicate blood vessels that exist throughout your body. They transport blood, nutrients and oxygen to cells in your organs and body systems. Capillaries are the smallest blood vessels in your vascular system.

Question 41

What is coronary artery disease?

Answer 41

The most common heart problem is coronary artery disease, which can lead to a heart attack. Coronary arteries are the blood vessels that carry blood to the heart muscle. Sometimes these arteries become partially blocked by plaque. Plaque is a deposit of fat, calcium, or other substances carried by the blood. Plaque buildup can be the result of poor lifestyle choices or of heredity. When plaque buildup occurs, heart attacks often follow. When coronary arteries become completely blocked, the heart muscle no longer receives the oxygen it needs to function. The heart then stops and the tissue begins to die. Medical attention is needed immediately.

Question 42

Describe the importance of the respiratory system.

Answer 42

The respiratory system is the organ system that provides oxygen to the cells and removes carbon dioxide from the body. This system works closely with the circulatory system.

Question 43

Describe how the alveoli connect the respiratory system and the circulatory system.

Answer 43

The alveoli are in direct contact with capillaries of the circulatory system. Such intimate contact ensures that oxygen will diffuse from the alveoli into the blood. In addition, carbon dioxide will diffuse from the blood into the alveoli to be exhaled.

Question 44

How is the digestive system connected to the circulatory system?

Answer 44

The digestive system breaks food down into nutrients such as glucose. Now the circulatory system enters the picture. It transports glucose and other nutrients from the digestive system to the cells. The circulatory system also transports oxygen from the lungs to the cells. Now the cells have what they need for cellular respiration: oxygen and glucose.

Question 45

Name some benefits and risks of organ transplantation

Answer 45

The main risk for transplant patients is organ rejection.
Benefits are: New healthy organ, living longer, correcting or fixing injuries or disabilities that can endanger someone’s life, improved quality of life, avoid A recipient’s immune system may recognize the new organ as a foreign material and try to destroy it. Because of this, transplanted tissues must be genetically similar to the recipient. Most transplant patients must take drugs to reduce the risk of rejection.
being hospitalized

Question 46

Explain what xenotransplantation

Answer 46

Xenotransplantation is the transplanting of body parts from one species to another. Heart valves from pigs have been used to replace damaged heart valves in humans. Before the valves can be implanted in a human, they must first be treated to kill the pig’s cells, so the tissue is no longer living.