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Biology > Chapter 3 > Flashcards

Chapter 3 Flashcards

1
Q

How to calculate magnification

A

mag= size of image / size of object
object= image / mag
image= mag * object
(must all be the same units)

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2
Q

How to convert units of length

A

km -> m *1000
m-> mm *1000
mm-> um *1000
um -> nm *1000

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3
Q

What is resolution?

A

The minimum distance apart that two objects can be in order for them to appear as separate items, which depends on the length of the wavelength of the microscope

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4
Q

What is cell fractionation?

A

The process of breaking open cells and isolating different organelles

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5
Q

What are the conditions for fractionation and why are they necessary?

A

Cold- to prevent the lysosomes (enzymes- get denatured) to destroy the organelles in the cell
Isotonic- to prevent organelles bursting from osmosis
Buffered- to keep the pH constant, as pH can alter the shape of organelles or affect the functioning enzymes

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6
Q

What is homogenation?

A

Breaking open the cells by a blender, or pestle and mortar

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7
Q

What is ultracentrifugation?

A

Separating the organelles in a machine called a centrifuge

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8
Q

How does ultracentrifugation work?

A

By spinning, the heaviest organelles, the nuclei are forced to the bottom of the eppendorf and the supernatant is removed from the top, where it is spun at a higher speed, so the next heaviest organelles are collected at the bottom of the eppendorf etc.

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9
Q

What is the order of cell organelles which are separated during centrifugation?
Never Call My Cousin Liam, Mark or Rhonda

A

Nuclei and cytoskeletons, mitochondria, chloroplasts and lysosomes, microsomes, ribsosomes
NCMCLMR

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10
Q

What is a graticule?

A

A glass disk attached to the eyepiece of a microscope that has a scale etched into it

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11
Q

Can the particular be used to directly measure the size of an object under the microscope? Why?

A

No, it must be calibrated otherwise it doesn’t consider the magnification

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12
Q

What is the definition of a eukaryotic cell?

A

A cell with membrane-bound organelles (nucleus that contains DNA)

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13
Q

What are the organelles and properties of a eukaryotic cell (in size order)?

A

Nucleus, chloroplasts, mitochondria, golgi apparatus, lysosomes, endoplasmic reticulum, vacuole, cell wall, cell surface membrane, ribosomes

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14
Q

Nucleus

A

Made of the nuclear envelope which controls the movement of materials in and out of the nucleus and reactions taking place in it, nuclear pores which allow some molecules to cross the envelope, chromosomes which are bundles of DNA, the nucleolus which makes ribosomes

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15
Q

Chloroplasts

A

Carry out photosynthesis, has an envelope to control what goes in and out, grana (high surface area), which are stacks of thylakoids which contains chlorophyll, the stromal, where photosynthesis is completed

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16
Q

Mitochondria

A

Have a double membrane, with the inner layer folded into cristae to increase SA, inside is the matrix where respiration is mainly carried out

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17
Q

Golgi apparatus

A

Made of stacks of membranes that make flattened sacs (called cisternae), is where proteins are synthesized, carbohydrates are added to proteins, produces some enzymes, and form lysosomes

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18
Q

Lysosomes

A

Made in the golgi apparatus, contains enzymes that destroy the material outside of the cell and the cell after it has died

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19
Q

Endoplasmic reticulum

A

Is continuous with the nuclear envelope, and enclose cisternae, rough ER has ribosomes to increase SA and produce proteins, smooth ER appears more tubular and synthesizes, stores and transports lipids and carbohydrates

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20
Q

Vacuole

A

Is much bigger in plant cells, and are fluid filled sacs, usually from waste materials from the cell, in plants, they make some cells turgid so are part of its structure, can act as temporary food stores, and colour the petals

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21
Q

Cell wall

A

In plants, made of cellulose so contribute to the strength of the cell, especially considering osmosis, encourages movement of water within the plant (outside of the cells)

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22
Q

Cell surface membrane

A

Partially permeable and made of a lipid bilayer, with embedded proteins

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23
Q

Ribosomes

A

Synthesize proteins and make RNA, they are made of two sub units, on larger, one smaller

24
Q

What happens to cells that are produced by mitotic divisions of the embryo?

A

They are specialised, so some cells have particular genes expressed, and the rest of the genes are switched off

25
Q

How are specialised cells different from each other?

A

They will have differing numbers of organelles (eg. muscle cells have lots of mitochondria and less lysosomes, bone cell has less mitochondria and more lysosomes) and the shape of the cells

26
Q

A tissue is…

A

Specialised cells aggregated together for efficiency

27
Q

Name a human tissue

A

Epithelial tissues, which consist of sheets of cells in animals to line particular organs to protect or secrete substances. Often well adapted for diffusion, such as oxygen from the lungs and products of digestion in the small intestine

28
Q

Name a plant tissue

A

Xylem, made of collected similar cell types, used to transport water and mineral ions through a plant

29
Q

An organ is…

A

Tissues aggregated together that coordinate to perform specific functions

30
Q

Name three different tissues in the stomach and their purposes

A

Muscle, to churn and mix the contents of the stomach
Epithelium, to protect the stomach wall from the hydrochloric acid and to produce secretions
Connective tissue, to join the different tissues

31
Q

Multiple organs working together are called…

A

An organ system

32
Q

Name an organ system and the functions of the organs (7) it is made up of

A

Digestive system, made up of salivary glands and pancreas which produce enzymes, the oesophagus to transport food, the liver which produces bile, the stomach which churns up food and begins to hydrolyse proteins, the duodenum and ileum, which secrete enzymes to hydrolyse food and then absorb these products

33
Q

Name two organ systems (that aren’t the digestive system)

A

The respiratory and circulatory systems

34
Q

DNA of prokaryotic cells

A

No true nucleus- only an area where DNA is found
DNA not associated with proteins
Some DNA formed in a circular strand called plasmids

35
Q

Organelles in prokaryotic cells

A

No membrane bound organelles
Ribosomes are smaller
No chloroplasts- only bacterial chlorophyll associated with the membrane in some bacteria
Cytoplasm jelly-like containing enzymes and other soluble materials

36
Q

Outer layer of prokaryotic cells

A

Cell surface membrane
Cell wall made of murein (10-80nm)
May have an outer layer called a capsule to protect cell wall
Some bacteria have a flagellum for locomotion

37
Q

Define a virus

A

Viruses are acellular, non-living particles that are smaller than bacteria (20-300nm)

38
Q

Properties of viruses

A

Viruses contain nucleic acids but can only multiply in living host cells
Nucleic acids contained in a capsid- a protein coat
Viruses protected further by a lipid envelope- have attachment proteins for identifying and attaching to host cells

39
Q

Define mitosis

A

The division of a cell resulting in two genetically identical daughter cells

40
Q

What are the four phases of mitosis?

A

Prophase, metaphase, anaphase and telophase

41
Q

What is a chromatid?

A

One copy of a chromosome (one half of the X chromosome shape)

42
Q

What is a chromosome?

A

A thread of genetic information that condenses to form an X shape. Can be the whole X or half of it: a single chromatid or both

43
Q

What is a centromere?

A

The centre of the X- where both chromatids are joined together

44
Q

What is a centriole?

A

Found in pairs, during mitosis they move to the poles of the cell and produce spindle fibres to separate the chromatids

45
Q

What happens in prophase?

A

Chromosomes have copied and become visible, as nuclear envelope fragmented. They condense to form X shape so they are easier to separate, but are loose and random in the cell. Centrioles are beginning to move to the poles of the cell

46
Q

What happens in metaphase?

A

The chromosomes line up along the equator of the cell. The centrioles are found at the poles and produce the spindle fibre, which attachs to the centromeres of the chromosomes

47
Q

What happens in anaphase?

A

The spindle shortens separating the chromatids, so the chromosomes move to the poles. This requires energy, so mitochondria move to the spindle fibres

48
Q

What happens in telophase?

A

As the chromosomes are now at the poles, the nuclear membrane starts to reform around both sets of chromosomes so they become impossible to see again. Th spindle fibre disintegrates and the cytoplasm divides, so the membrane begins to close off both sides from the other- this is cytokinesis- as the two parts of the cell separate

49
Q

What is cell division in prokaryotic cells called?

A

Binary fission

50
Q

What is binary fission?

A

The circular DNA replicates and both copies attach to the cell membrane
The plasmids also replicate
The cell membrane grows between the two DNA molecules and pinches inward, dividing the cytoplasm
A new cell wall forms between the two DNAs, separating the cell into two

51
Q

Replication of viruses

A

They attach to their host cell with the proteins on the surface and inject their nucleic acid into the host cell. The host cell then starts producing viral components, nucleic acid, enzymes and structural proteins which are assembled into new viruses

52
Q

Mitosis is important for…

A

Growth, repair and reproduction (for single-celled organisms)

53
Q

What are the phases in the cell cycle and how long does the process take?

A

G1, S, G2 and mitosis, which take 24 hours to complete (mitosis takes 20 minutes, unless they are cancerous cells-which speed up the cell cycle, or nerve cells- which never complete mitosis)

54
Q

What is G1, S and G2 summarised as?

A

Interphase, where the cell is preparing for mitosis. G1 produces more organelles (like mitochondria for energy and ribosomes etc.). S (synthesis) replicates the DNA as chromatin-where the DNA is loosely coiled up and not in the form of chromosomes. G2 is the increase of the mass of the cell.

55
Q

What is the cause of cancer?

A

Cells that do not replicate and grow properly. So mitosis isn’t regulated properly and uncontrollable growth occurs

56
Q

How is cancer treated?

A

Usually, chemicals are used to disrupt part of the cell cycle, essentially ceasing cell growth. Chemotherapy either prevents the DNA from replicating (in the S phase), or inhibits metaphase by interfering with spindle formation

57
Q

What is the main problem with chemotherapy as a cancer treatment?

A

Disrupting the cell cycle would also damage the growth of normal cells. However, because cancerous cells replicate at a faster rate, the chemicals act on these cells rather than normal ones. Though normal, quickly dividing cells like hair-producing cells are also damaged: leading to hair loss

Biology (5 decks)

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