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Cell Biology > Chapter 1 - An Overview Of cells and Cell Research > Flashcards

Chapter 1 - An Overview Of cells and Cell Research Flashcards

1
Q

What is the major cell biology concept of this chapter?

A

Compartmentalization of cellular components into organelles divides different functions into separate cellular regions, allows targeting of molecular complexes within the cell, and increases the efficiency of biochemical pathways.

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2
Q

What are genes?

A

Segments of DNA that encode proteins or RNA which are the functional units of inheritance.

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3
Q

What is transcription?

A

When the nucleotide gene sequence is copied into RNA.

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4
Q

What is translation?

A

When a nucleotide sequence of RNA is used to specify the order of amino acids into a protein.

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5
Q

What are the two types of cells?

A

Eukaryotic and prokaryotic

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6
Q

What are the major difference between the two types of cells?

A

Eukaryotic cells have a nucleus which separates the genetic material from the cytoplasm. Prokaryotic cells have no nucleus.

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7
Q

Which cell has no organelles?

A

Prokaryotes

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8
Q

What is the critical characteristic of nucleic acids?

A

They self-replicate.

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9
Q

What are the four nucleotides?

A

Adenine goes with Uracil

Guanine goes with cytosine.

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10
Q

Why is complementary pairing important?

A

One strand of RNA can act as a template for the synthesis of a new strand.

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11
Q

What is a phospholipid molecule composed of?

A

Hydrophilic head and two hydrophobic tails

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12
Q

What do cells use for metabolic energy?

A

adenosine 5′-triphosphate (ATP)

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13
Q

ATP mechanisms evolved in three stages, what are they?

A

Glycolysis, photosynthesis, and oxidative metabolism

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14
Q

What is glycolysis?

A

The anaerobic breakdown of glucose into lactic acid

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15
Q

How many ATP molecules does one glucose molecule produce during glycolysis?

A

Two ATP

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16
Q

What is photosynthesis?

A

Uses sunlight to drive synthesis of glucose from CO2 and H2O which creates glucose and releases O2 as a by-product

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17
Q

What is oxidative metabolism?

A

Glucose and oxygen produced are broken down into CO2 and H2O

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18
Q

How many ATP molecules are produced during oxidative metabolism?

A

36-38

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19
Q

What are archaebacteria?

A

Prokaryotic, live in extreme environments

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20
Q

What are cyanobacteria?

A

Prokaryotic, photosynthesis evolved here and are the largest and most complex prokaryotes

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21
Q

Where does DNA replication and RNA synthesis occur in a eukaryotic cell?

A

Nucleus

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22
Q

Where does oxidative metabolism occur?

A

Mitochondria

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23
Q

Where does photosynthesis occur?

A

Chloroplasts

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24
Q

What is the function of E.R.?

A

Functions in processing and transporting proteins and lipid synthesis.

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25
Q

What do lysosomes and peroxisomes do?

A

Digest macromolecules and are the site of various oxidative reactions

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26
Q

What are vacuoles?

A

Only in plant cells, digest , digest macromolecules and store waste products and nutrients

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27
Q

The functions of a cytoskeleton include;

A

Providing structural framework, determines cell shape and organization, and is involved in movement of whole cells, organelles, and chromosomes during cell division.

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28
Q

What is endosymbiosis?

A

Prokaryotic cells living inside the ancestors of eukaryotes.

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29
Q

What is the evidence for endosymbiotic origin?

A

Mitochondria and chloroplasts are similar in size. Reproduce by dividing in two. Contain their own DNA and replicate the DNA when the organelle divides. Genes then transcribe within the organelle and then translated on organelle ribosomes. ribosomes and ribosomal RNAs are more closely related to those of bacteria than to those encoded by the eukaryote nuclear genome.

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30
Q

Simplest eukaryotes?

A

Yeast

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31
Q

When did multicellular organism evolve?

A

1-2 billion years ago

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32
Q

5 tissue types of animals

A

Epithelial, connective, blood, nervous, and muscle

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33
Q

Epithelial cells

A

Form sheets that cover the surface of the body and line internal organs

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34
Q

Connective

A

Bone, cartilage, adipose.

35
Q

Loose connective tissue is formed by?

A

Fibroblasts

36
Q

Erythrocytes

A

Red blood cells that function in oxygen transport

37
Q

Types of white blood cells include

A

Granulocytes, monocytes, macrophages, and lymphocytes

38
Q

White blood cell function

A

Function as an inflammatory reactions and the immune response

39
Q

Nervous tissue include

A

Neurons, sensory

40
Q

Why is E. Coli. useful as an experimental cell model?

A

Simple and easy to culture (divide every 20 minutes), genome consists of about 4.6 million base pairs and has about 4300 genes (small genome), can carry out biosynthetic reactions in media that helped define biochemical pathways, easy to isolate clones, simple nutritional requirements

41
Q

What bacterium paved the way for understanding DNA replication, genetic code, gene expression, and protein synthesis?

A

E. Coli.

42
Q

Why is Saccharomyces cerevisiae used as an experimental model?

A

Yeast are simplest eukaryotes, 12 million base pairs of DNA and 6000 genes, easy to grow, yeasts apply to all eukaryotic cells,

43
Q

Why is Caenorhabditis elegans used as an experimental model?

A

Nematode, small genome but 19,000 genes (almost same number as humans), embryonic origin and lineage of all the cells have been traced because only 959 somatic cells

44
Q

Why is Drosophila melanogaster a biological model?

A

Short reproductive cycle useful for genetic experiments, similar genes and mechanisms exist in vertebrates

45
Q

What is the model for plant molecular biology?

A

Arabidopsis thaliana

46
Q

Why is Arabidopsis thaliana a useful model?

A

Small genome and easily grown in lab. Helped identify development of flowers

47
Q

Why are zebrafish used as a model?

A

Small and reproduce rapidly, embryos develop outside of a mother and are transparent which makes development easy to observe, helps bridge the gap

48
Q

Why are mice used for cell study?

A

Human and mouse genomes are similar and mutations in homologous genes result in similar developmental defects

49
Q

Who proposed the cell theory?

A

Schleiden and Schwann (1838)

50
Q

Who discovered the cell?

A

Robert Hooke

51
Q

Advantages of in vitro studies

A

Study cell growth and differentiation, perform genetic manipulations

52
Q

What is it called when an initial cell culture is isolated from a tissue?

A

primary culture

53
Q

How do you make a secondary culture?

A

Re-plate primary culture many times to reduce the density

54
Q

What are usually used as starting cell cultures? Why?

A

Embryos or tumors because they can grow rapidly.

55
Q

Advantage of using embryonic stem cells?

A

Can differentiate into all of the cell types of the adult organisms

56
Q

What are viruses?

A

Intracellular parasites that cannot replicate on their own.

57
Q

How to viruses reproduce?

A

Infecting host cells and overtaking the cellular machinery to produce more virus particles.

58
Q

What do viruses contain?

A

DNA or RNA surrounded by a protein coat

59
Q

What are retroviruses?

A

Have RNA genomes but synthesize a DNA copy of their genome in infected cells. First virus that demonstrated the synthesis of DNA from RNA templates.

60
Q

What are cell lines?

A

When viral genes are introduced to secondary cultures to disrupt the normal cell cycle to control growth. The new clones are isolated and used for future studies.

61
Q

Who found that DNA tumor viruses converted normal animal cells into cancer cells?

A

Peyton Rous (1911)

62
Q

Why is the knowledge about DNA tumor viruses important?

A

Help understanding about cancer and molecular mechanisms that control animal cell growth and differentiation. Helped develop vaccines to prevent cancer (HPV)

63
Q

What is resolution?

A

The ability to distinguish objects separated by small distances. More important than magnification.

64
Q

What is the limit of resolution determined by?

A

Wavelength and numerical aperture (NA) which is the light-gathering power of the lens.

65
Q

What is the formula for determining resolution?

A

(0.61 times wavelength) / NA

66
Q

What is the theoretical limit of resolution of a light microscope?

A

0.22 micrometers

67
Q

What is bright-field microscopy?

A

Light passes directly through the cell. Cells usually preserved with fixatives and stained with dyes for observation.

68
Q

Can bright-field microscopy be used to study living cells?

A

No

69
Q

What are the similarities of phase-contrast microscopy and differential interference-contrast microscopy?

A

Can observe living cells before and after cell culturing.

Converts variations in density or thickness to different contrasts in final images.

70
Q

What type of data is obtained from fluorescence microscopy?

A

Qualitative (visual analysis)

71
Q

How does fluorescent microscopy work?

A

Dye molecules attached either directly or indirectly to a molecule of interested in fixed or living cells absorb light at one wavelength and emit light at a different wavelength. A wavelength that illuminates the specimen is recorded by filters.

72
Q

What are the advantages of confocal microscopy?

A

Increases contrast and detail by analyzing fluorescence from a single point.

73
Q

How does confocal microscopy work?

A

A small point of light from a laser is focused on the specimen at a particular depth. The emitted fluorescent light is collected using a detector like a video camera. The emitted light passes through a confocal aperture in which only light emitted from the plane of focus within the specimen reaches the detector. A series of 2D images of the plane of focus are constructed into a 3D image.

74
Q

What are the advantage of electron microscopy?

A

Much greater resolution (0.2-nanometers) then light microscopy (this is due to the short wavelengths of electrons)

75
Q

How does transmission electron microscopy work?

A

Specimens are fixed and stained with salts of heavy metals which provide contrast by scattering electrons. A beam of electrons is passed through the specimen and forms an image on a fluorescent screen. Gram positive or negative.

76
Q

What is an advantage of scanning electron microscopy?

A

Provides a 3D image of cells.

77
Q

How does scanning electron microscopy work?

A

The surface of the cell is coated with a heavy metal and a beam of electrons is used to scan across the specimen. (electron beam does NOT pass through the specimen)

78
Q

Why was differential centrifugation developed?

A

To separate cell components on the basis of size and density to study the function of each organelle. (1940s and 50s)

79
Q

What are the three ways plasma membranes and endoplasmic reticulum are fragmented?

A

Sonication, grinding, or high-speed blending.

80
Q

After fragmentation of plasma membranes or E.R., what is done to the suspension?

A

Suspension is fractionated in an ultra-centrifuge

81
Q

Larger, more dense organelles sediment at _______ speeds while small organelles sediment at ______ speeds

A

Lower ; High

82
Q

What is supernatant?

A

Remaining solution

83
Q

What is density-gradient centrifugation?

A

Organelles are separated by sedimentation through a gradient of dense substance such as sucrose.

84
Q

What is velocity centrifugation ?

A

Starting material is layered on top of the sucrose gradient. Particles of different sizes sediment through the gradient at different rates.

Cell Biology (2 decks)

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