Cells

Question 1

What are the different levels of organization of life?

Answer 1

1. atoms
2. molecules
3. cells
4. tissues
5. organs
6. systems
7. organism

Question 2

What are the four types of molecules?

Answer 2

1. lipids
2. proteins
3. nucleic acid
4. carbohydrates

Question 3

What are the three common structures present in a cells?

Answer 3

1. nucleus
2. cytoplasm
3. cell membrane

Question 4

What are the role/function of the nucleus, cytoplasm, and the cell membrane

Answer 4

Nucleus: code for everything that you body is or does
Cytoplasm: structure and support
Cell membrane: protect structure

Question 5

Explain why the shape of a specific cell is adapted to its function

Answer 5

The cell is usually related to its function (red blood cell is disc-shaped so they can carry more oxygen, neurons as dendrites to catch as many signals as possible, etc)

Question 6

Provide examples of cells, organs, and systems in the human body

Answer 6

Cells: blood cells, nerves cells, sperm cells
Organs: Heart, brain, lungs
Systems: nervous system, endocrine system, reproductive system

Question 7

What are the functions of sexual reproduction?

Answer 7

-maintain and increase the number of human
-increase genetic diversity
-allows natural selection to happen

Question 8

what are chromosomes?

Answer 8

threads-up structure made of DNA

Question 9

What is the difference between haploid and diploid cells?

Answer 9

haploid: contains one set of chromosomes
diploid: contains two set of chromosomes

Question 10

What is the difference between somatic and germ cells?

Answer 10

somatic cells: non-reproductive cells (ex: hair, skin, nails) -diploid
germ cells: reproductive cells (ex: sperm, ova) - haploid

Question 11

Interpret a karyotype

Answer 11

• X,X = female
• X,Y = male
• three chromosomes = down syndrome
• when female have only one X = turner syndrome
• down and turner syndrome are the only two that are compatible with life

Question 12

What is the function of meiosis and how does it creates unique gametes?

Answer 12

• it’s for genetic variety
• 46 chromosomes and 92 chromatids to 23 chromosomes and 46 chromatids t0 23 chromosomes and 23 chromatids (4 sperm or 1 ova)

Question 13

What are the structure involved in human gametes production and regulation?

Answer 13

Sperm (haploid (n=23)):
- human male reproductive cells
- contains many mitochondria that give them enough energy to swim to the ovum
- produce in testis
- regulated by:
hypothalamus: produce GnRH
anterior pituitary: produce FSH-LH
Leydig cells (in testis): testosterone (the sperm need testosterone because without it it is not mature enough

Ova (haploid n=23))
- human female reproductive cells
-founds in the ovaries
-every month from puberty to menopause, one (or more) primary egg cell will mature into a secondary egg cell ready for fertilization
- a female is born with all her egg, if two eggs are release = twin who are genetically different

Question 14

What is the trajectory of gametes (sperm) during human reproduction?

Answer 14

1. Testis: sperm production
2. epididymis: sperm maturation
3. vas deferens: sperm stays there until ejaculation
4. seminal vesicle: add prostaglandins (hormones that makes contract)
5. Prostate gland: adjust the ph of the sperm + liquid that thicken the sperm

Question 15

What is the trajectory of gametes (ova) during human reproduction?

Answer 15

1. Primary follicle
2. Growing follicle
3. Mature follicle
4. Ovulation
5. Empty follicle
6. Corpus luteum
7. Corpus luteum regressions

Question 16

Understand the process of fertilization

Answer 16

• the fertilization need to occurs around day 14
• FSH-LH: growing egg cell into actual egg and when they are mature they are ready to ovulates so if no FSH no egg can be ready to ovulate so no ovulation

Question 17

What are the function of mitosis?

Answer 17

• cell replication (no change in the ploidy)
• produces 2 identical daughter cells
• involve in growth and in replacing worn-out damaged cells

Question 18

What are the role of hormones in growth, including the organs producing them and their regulation?

Answer 18

• Growth hormones (GH) stimulates the growth of many tissues including bone and cartilage tissues
• GH is regulated by:
  hypothalamus (GHRH: growth hormones releasing hormones)
  anterior pituitary (GH: growth hormones)
  Liver( IGF) and other tissues: insulin growth factors
• many other hormones are involve in growth
• abnormal levels of growth: giantism (too much hormones)
  pituitary dwarfism (not enough mitosis is performed)

Question 19

Compare meiosis and mitosis

Answer 19

Meiosis: more complicated, involve in reproduction, gametes (1n) unique cell, 4 sperm or 1 ova
Mitosis: simpler, process of human growth, general repair, and maintenance (ex: if you hurt yourself), somatic cell (2n), identical daughter cell, 2 cells

Question 20

What are the parts and functions of neurons?

Answer 20

Functions:
- Produce and send messages by electrical messaged,
- Regulate glands,
- Activates/inhibits muscle contraction,
- Thinking
- Sensing/perception (neuron receive message and send it to your brain

Parts of neurons:
- Nucleus
- Cell body
- Dendrites: responsible for catching signals
- Axon hillock: you need certain amount of signals before sending them.
- Myelin: protective layers that keep the signals in the axon,
- Axon terminal: send axon to its target,
- Axon: where the electrical impulse travel
- Glial cells: physical and chemical support to the neurons

Question 21

How are neurotransmitters are released through the synapse?

Answer 21

When the action potential arrives at the end of the neuron, neurotransmitter is release into the synapse and they go fit into receptor

Question 22

What are the types of neuroglia?

Answer 22

1. Astrocytes
2. Microglia
3. Ependymal
4. Oligodendrocytes

Question 23

Astrocytes - neuroglia (function)

Answer 23

• In the central nervous system (brain and spinal cord)
• Support neurons
• Protect neurons from harmful substances.
• Help maintain a proper chemical environment for the generation of nerve impulses

Question 24

Microglia - neuroglia (function)

Answer 24

• In the central nervous system (brain and spinal cord)
• Protect brain and spinal cord from microbes,
• Migrate to damage areas to clear debris and dead cells

Question 25

Ependymal - neuroglia (function)

Answer 25

- In the central nervous system, - Line cavities of the brain - Form cerebrospinal fluid and assist in its circulation

Question 26

Oligodendrocytes - neuroglia (function)

Answer 26

- In the central nervous system, - Produce and maintain myelin sheath around axon in the brain, - Also exist in the peripheral nervous system, where they are called neurolemocytes (or shwann cells)

Question 27

What are the function of the endocrine cells?

Answer 27

- Endocrine system secrets hormones - Main function of hormones = regulates cell activity - Hormones bind to specific receptors on target cells, - Receptors may be at the surface of the cell’s membrane, or within the cell,

Question 28

Internal hormone receptors

Answer 28

- Receptors may be in the cytoplasm or in nucleus, - For hormones that can pass through the cell membrane (fat-soluble) - When the hormones bind to the receptor, it usually activates genes --- leads to the production of proteins, - Main type of fat-soluble hormones steroids Examples: 1. Estrogen: female reproductive system 2. Testosterone: male reproductive system 3. Glucocorticoids (ex: cortisol): stress response

Question 29

Surface hormone receptor

Answer 29

- Receptors on cell exterior - For hormones that cannot cross the cell membrane (water-soluble) - When hormones (1st messenger) binds to surface receptor, a 2nd messenger is activated. - Main type of water-soluble hormones: peptide hormones Example: 1. Insulin: the hormone produces by pancreas to metabolise excess sugar, 2. Glucagon: opposite effect of insulin – turns… into sugar to turn it into energy, 3. Epinephrine/adrenaline activates metabolic pathway: naturally produce into the body--

Question 30

What are the function of the hypothalamus and the pituitary gland?

Answer 30

- Hypothalamus: a. Mastermind of the endocrine system b. 50% endocrine tissue, 50% nervous tissue c. Produces releasing hormones (RH) that tell the pituitary gland to release hormones, d. In turn, the pituitary gland releases hormones that stimulate other glands, - Posterior pituitary gland: a. Does not synthesize its own hormones, b. Releases the hormones that the hypothalamus sends, c. Can also inhibit the release of hormones, - Anterior pituitary gland: a. Synthesize its own hormones

Question 31

Explain the process of aging?

Answer 31

-Telomeres (aging = shortening of telomeres): a. Telomeres protect coding regions (genes) at the end of each chromosome, b. With each successive cell division (DNA replication), telomeres become shorter, c. When telomeres are excessively short, cells die (apoptosis = when cells want to replicate but no more telomeres so they kill themselves), d. As we get older, we lose telomeres as the genes replicate,

Question 32

What is the relationship between cell division and cancer?

Answer 32

- Cell division is controlled by checkpoints, - If there is a change in the DNA (a mutation), it is either fixed or the cell dies (apoptosis), - Mitosis is a cycle and there are often checkpoints to look if everything is good before going into mitosis. - There’s a mutation – cell detect it – fixes the mutation or apoptosis, - There’s a mutation—cell doesn’t detect it—cells die accidentally (mutation cause change in the cell and the cell accidentally dies) or cancer (the cell doesn’t detect the mutation but the mutation is not bad enough for the cell to die immediately, so she replicate with the mutation and develop into more cancer cells).

Question 33

How cancer cell characteristics and behaviours are linked?

Answer 33

- Have an increase and uncontrolled cell cycle, - Do not undergo programmed cell death, - Can spread to other regions of the body, - Cause the growth of new blood vessels, - Can cause mal function in the body, e) Environmental – UV/sun can develop into skin cancer, f) Breast cancer—genetic mutation g) Can also be random (and cells end up spreading)