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Science Revision > Cells > Flashcards

Cells Flashcards

1
Q

What is the definition of eukaryotic cell?

A

A cell with dna in the nucleus and membrane bound organelles, bigger than prokaryotic cells

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2
Q

What is an example of a membrane bound organelle?

A

Mitochondria

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3
Q

How are prokaryotic cells different from eukaryotic cells?

A

They are smaller and have no nucleus, rather the dna is floating about in the cytoplasm. Some dna are in plasmids

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4
Q

What is the function of nuclei?

A

Stores genetic information and controls the activities of the cell

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5
Q

What is the function of cytoplasm?

A

Where the chemical reactions take place

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6
Q

What is the function of ribosomes?

A

Site of protein synthesis

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7
Q

What is the function of the vacuole?

A

Helps the cell keep its shape and stores water

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8
Q

What is the function of the cell wall?

A

Protects the cell. Very rigid and sturdy, and made of cellulose

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9
Q

What is the function of the chloroplasts?

A

Contains chlorophyll and is a site of photosynthesis which produces energy from sunlight, chloroplasts make the plant green

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10
Q

What is the function of pili?

A

For sticking to surfaces and other cells

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11
Q

What is the function of plasmids?

A

Extra lots of circular dna, can be for antibiotic resistance. Some produce toxins

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12
Q

What type of organelles do animal cells have? (5)

A

Nuclei, mitochondria, ribosomes, cell membrane, cytoplasm,

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13
Q

What type of organelles do plant cells have? (8)

A

Nuclei, mitochondria, ribosomes, cell membrane, cytoplasm, Chloroplasts, vacuole, cell wall

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14
Q

What type of organelles do prokaryotes have? (6)

A

Cell wall, plasmids, pili, cytoplasm, capsules, flagella

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15
Q

What is the function of flagella?

A

Movement

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16
Q

What is the cell wall (membrane?) in prokaryotes made out of?

A

peptidoglycan

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17
Q

Pre-1970, how were living things classified?

A

Into five kingdoms, based on observable traits

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18
Q

Post-1970, how were living things classified?

A

Into three domains

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19
Q

What are archaea?

A

Small, single called organisms that live in extreme environents (extremophiles)

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20
Q

Why were archaea and bacteria separated into two separate domains?

A

woesse decided that if these organisms (archaea) lived in extreme environments, they must be different

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21
Q

What are the differences between archaea and bacteria?

A
  • dna sequencing shows their DNA is very different
  • archaea ribosomes have nucleic acids more like eukaryotes
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22
Q

What kind of places can archaea live in?

A

Salt planes, very hot water, deep water, etc

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23
Q

What are the parts of a microscope? (4)

A

Eyepiece lens, objective lens, fine and coarse focusing knobs

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24
Q

What is the eyepiece lens for?

A

The first stage of magnification, where you look into the microscope

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25
Q

What is the objective lens for?

A

second stage of magnification,changes how closely magnified the image is.

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26
Q

What is the fine + coarse focusing knobs for?

A

Fine-tuning the image; viewing the details and rough focusing respectively

27
Q

What is the definition of magnification?

A

The ability of a lens or other optical instrument to magnify (enlarge) the size of something in the optical

28
Q

What is the definition of resolution?

A

The ability of a microscope to distinguish between two adjacent points as seperate

29
Q

What is the definition of maximum resolution?

A

The smallest distance between two points, at which they can be recognised as separate entities. The better the resolution, the easier you can view & identify finer details

30
Q

Who was Ernst Ruska?

A

A German physicist who won the 1986 Nobel

physics prize for his work on electron optics, including the invention of the electron microscope.

31
Q

Who was Anton von Leeuwenhoek ?

A

A Dutch businessman and scientist, and the first person to see bacteria after looking closely at water with a microscope.
Some of his other discoveries include blood and sperm cells

32
Q

Who was Robert Hooke ?

A

The first person to see a microorganism with a microscope. He named cells and wrote a book (micrographia) about his findings.

33
Q

Who invented the electron microscope?

A

Ernst Ruska

34
Q

How can you calculate total magnification in a microscope? (And which variables are fixed and which can change?)

A

Magnification of eyepiece lens* x magnification of objective lens**

  • fixed
  • *can change between x4 x10 x40 x10p
35
Q

What are the disadvantages of electron microscopes?

A

Can only see in black and white, very expensieve, very big, not portable, can either be SEM or TEM, thing you’re looking at must be dead

36
Q

What are the disadvantages of light microscopes?

A

Less magnification and resolution

37
Q

What are the advantages of light microscopes?

A 
Portable
see in colour
specimen can be alive
cheaper
can be used by anyone
smaller
38
Q

What are the advantages of electron microscopes?

A

Greater magnification and resolution
can see inside cell
no complex lighting

39
Q

What are the two types of electron microscope?

A

Scanning electron microscopes (SEM) and transmission electron microscopes (TEM)

40
Q

What are movement, respiration, growth, reproduction, excretion and nutrition?

A

Life processes

41
Q

What do cells group together into?

A

Tissues

42
Q

How many times can an electron microscope magnify up to compared with a light microscope

A

2 million times (electron)

2,000 times (light)

43
Q

How does the electron microscope work?

A

Uses electron beams instead of light beams, and the electrons bounce off surface of a specimen that has a very thin coating of a gold-like metal

44
Q

What does a scanning electron microscope do?

A

The electrons scan a sample’s surface

45
Q

What does a transmission electron microscope do?

A

The electrons penetrate a sample’s surface to see inside

46
Q

“Explain how electron microscopes have increased out knowledge of sub cellular structures.”

A

“An electron microscope has a much higher magnification and resolving power, meaning it can be used to study cells in more detail. Scientists can now see and understand sub cellular structure.”

47
Q

What is resolving power?

A

The ability of a microscope to distinguish between two adjacent points (resolution)

48
Q

What is the smallest thing we can see? (With the naked eye?)

A

0.04mm

49
Q

How do you calculate magnification of an image?

A

Image size / actual size

50
Q

How do you calculate image size?

A

Magnification x actual size

51
Q

How do you convert out of standard form? (Example of 1.26 x 10^5)

A

The power of ten is how many times you move the decimal place to the /right/. If the power is negative, move to the /left/ instead.

52
Q

Why might mitochondria look different in different slides?

A

There might be mutations, different slices, natural differences or damages.

53
Q

What are stem cells?

A

Stem cells are unspecialised cells with the ability to duplicate / or duplicate and specialise

54
Q

What type of cells can embryonic stem cells differentiate into?

A

Any type

55
Q

What type of cells can umbilical cord stem cells differentiate into?

A

Blood

56
Q

What type of cells can normal stem cells differentiate into?

A

The type of cell from the tissue they are found in

57
Q

Where are embryonic stem cells found?

A

In the blastocyst, 3-5 days after fertilisation

58
Q

What is an immunosuppressant?

A

A drug that supremes an immune system so it doesn’t reject foreign tissue such as a transplanted heart

59
Q

Where are stem cells found in plants?

A

The meristem- the roots and shoots

60
Q

What diseases are stem cells being used to cure?

A

Parkinson’s and diabetes, specifically type 1

Also age related sight loss and paralysis

61
Q

What are therapeutic stem cells?

A

“Fake” stem cells that are grown from a half a nucleus of a patient and a donated egg cell (or vice versa, if the patient is female)
This means that the patient doesn’t have to take immunosuppressants

62
Q

Why can plant stem cells be useful?

A

Creating plants immune to disease, protecting endangered species, indentical plants for research,

63
Q

What is binary fission?

A

A type of asexual reproduction found in bacteria, where one organism splits to become two

Science Revision (55 decks)

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