Core Concepts: Cell Structure and Organisation Flashcards

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1
Q

What is the function of the nucleus

A

Contains the DNA which codes for protein synthesis

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2
Q

What is the function of the nuclear envelope

A

Separates the DNA from the cytoplasm

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3
Q

What is the function of the nuclear pore

A

Allows passage of molecules in and out on the nucleus

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4
Q

What is the function of the nucleolus

A

Synthesis of rRNA to make ribosomes

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5
Q

What is the structure of ribosomes

A
  • 2 subunits made from ribosomal RNA (rRNA) and protein:
    - Large subunit
    - Small subunit
  • Can be free or attached to rough endoplasmic reticulum (RER)
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6
Q

What is the function of ribosomes

A

Protein synthesis

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7
Q

What is the structure of mitochondria

A
  • Cylindrical and 1-10 um in diameter
  • Double membrane separated by the fluid-filled, inter membrane space
  • Inner membrane folded to form cristae
  • The interior is called the matrix and contains enzymes
  • contains DNA and ribosomes (70s)
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8
Q

What is the function of mitochondria

A
  • Site of aerobic respiration, synthesises ATP
  • Cristae increases surface area on which part of the respiratory process takes place
  • Cells with high metabolic activity contain many mitochondria
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9
Q

What is the RER

A

Rough Endoplasmic Reticulum

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10
Q

What is the structure of RER

A
  • A series of membrane, which enclose flattened sacs called cisternae
  • Continuous with the nuclear membrane
  • Has ribosomes attached
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11
Q

What is the function of RER?

A

Transports proteins which are synthesised by the ribosomes attached

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12
Q

What is the structure of smooth endoplasmic reticulum

A
  • Forms a system of flattened sacs (cisternae) which are continuous with the nuclear membrane
  • May link to the Golgi apparatus
  • Has NO ribosomes attached
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13
Q

What is the function of smooth endoplasmic reticulum

A

The synthesis and transport of lipids

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14
Q

What is the structure of golgi body

A
  • flattened sacs of membrane called cisternae
  • Surrounded by vesicles
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15
Q

What is the function of golgi body

A
  • Chemically modifies proteins
  • Produces lysosomes
  • Produces glycoproteins
  • Packages proteins for secretion out of the cell
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16
Q

What is the structure of vesicles

A

Small membrane bound organelle

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17
Q

What is the function of vesicles

A

Act as a contractile vacuole to maintain osmotic pressure

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18
Q

What is the the structure of vacuoles

A

Large membrane bound organelle surrounded by a tonoplast

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19
Q

What is the function of vacuoles

A
  • Storage of ions and organic molecules (e.g. proteins)
  • Maintaining osmotic pressure
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20
Q

What is the structure of centrioles

A

Two hollow cylinders positioned at right angles to one another

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21
Q

What is the function of centrioles

A

Used in spindle formation (microtubles) in cell division

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22
Q

What is the structure of lysosomes

A
  • Small vacuoles formed when small portions of the Golgi body are pinched off
  • Contain and isolate digestive enzymes
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23
Q

What is the function of lysosomes

A
  • Release digestive enzymes and destroy organelles
  • Digestion of material which has been taken into the cell
  • lysosomes isolate the potentially harmful enzymes from the rest of the cell
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24
Q

What is the structure of chloroplast

A
  • Have a double membrane
  • The interior is made up of a fluid called stroma containing:
    - ribosomes
    - lipids
    - circular DNA
    - starch granules.
  • There are thylakoids - flattened sacs. these form stacks which are called granum. Each granum consists of between 2-100 thylakoids. Between the grana the thylakoids form lamellae
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25
Q

What is the function of chloroplasts

A
  • Site of photosynthesis
  • The thylakoids contain photosynthetic pigments such as chlorophyll
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26
Q

What is the structure of a cellulose cell wall

A

Made of cellulose microfibrils in a polysaccharide matrix

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27
Q

What is the function of a cellulose cell wall

A
  • To provide mechanical strength and support
  • Freely permeable to water
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28
Q

What is the structure of plasmodesmata

A

A narrow thread of cytoplasm that passes through the cell walls of adjacent plant cells

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29
Q

What is the function of plasmodesmata

A
  • Exchange of large organic materials via cytoplasmic streaming
  • Allows communication between adjacent cells
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30
Q

What is the theory that describes the origin of chloroplasts and mitochondria

A

Endosymbiotic theory

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31
Q

What is the Endosymbiotic theory

A

Prokaryotes engulfed & internalised other prokaryotes

32
Q

What is the evidence for the endosymbiotic theory

A
  • Organelles self replicate
  • Same DNA and Chloroplastss early Bacteria
  • Inner membrane is similar in structure to original bacteria
33
Q

State the 9 steps for protein production

A
  1. Nucleus contains DNA, codes for the amino acid sequences in proteins
  2. An mRNA copy of the DNA is made by transcription. This is small enough to fit through the nuclear pore and goes into the cytoplasm
  3. The nucleus synthesises rRNA for ribosome production
  4. Ribosomes synthesise the protein using the mRNA (translation)
  5. RER transports protein
  6. Glogi body modifies protein (e.g. adding a prosthetic group) which is then packaged into a secretory vesicle
  7. Vesicle carrying the protein migrates towards the plasma membrane
  8. Vesicle fuses with the plasma membrane then the contents of the vesicle are emptied by exocytosis
  9. Mitochondria produces ATP which is used in active processes
34
Q

What is the definition of prokaryote

A

A single-celled organism with membrane-bound organelles and with its DNA free in the cytoplasm

35
Q

What is the definition of eukaryote

A

An organism containing cells that have membrane-bound organelles, with DNA in chromosomes within the nucleus

36
Q

What are the 2 types of viruses

A
  • DNA viruses
    - stable, do not mutate rapidly
    - Single-stranded or double-stranded
    - Smallpox, Hepatitis B
  • RNA viruses
    - mutate rapidly, unstable
    - Single-stranded or double-stranded
    - Influenza, HIV
37
Q

What types of cell do viruses infect

A
  • animal, plant and fungal cells
  • Viruses can also attack bacteria. These are called bacteriophage
38
Q

Describe the DNA in Prokaryotes

A
  • Circular
  • Naked DNA
  • Plasmids contain 1-3 genes
39
Q

Describe the DNA in Eukaryotes

A
  • Linear
  • Found in the nucleus
  • Associated with histone proteins
40
Q

Describe the DNA in Viruses

A

Core contains DNA or RNA

41
Q

Describe the organelles in Prokaryotes

A
  • No membrane bound organelles
  • Have Ribosomes (70s)
42
Q

Describe the organelles in Eukaryotes

A

Have membrane bound organelles:
* Nucleus
* Mitochondria
* RER
* SER
* Golgi Body
* Chloroplasts
* Vesicles
* Lysozomes
* Permanent vacuole
* Ribosomes (80s)

43
Q

Describe the organelles in Viruses

A

No organelles

44
Q

For each one, state whether a cytoplasm is present:

  • Prokaryotes
  • Eukaryotes
  • Viruses
A
  • Prokaryotes - Yes
  • Eukaryotes - Yes
  • Viruses - No
45
Q

Describe the boundaries of a Prokaryote

A
  • Cell Membrane
  • Cell Wall - peptidoglycan
  • Slime Capsule
46
Q

Describe the boundaries of a Eukaryote

A
  • Cell Membrane
  • Cell Wall:
    - Plants - Cellulose
    - Fungi - Chitin
47
Q

Describe the boundaries of a Virus

A
  • Capsid - Protein
  • Lipoprotein Coat
48
Q

Describe the replication of a Prokaryote

A

Self replication by Binary Fision

49
Q

Describe the replication of Eukaryotes

A

Self replication by mitosis

50
Q

What do all Prokaryotes contain

(5 answers)

A
  • DNA molecules loose in cytoplasm
  • Peptidoglycan Cell Wall
  • 70s Ribosomes
  • Cytoplasm
  • Cell Membrane
51
Q

What do some Prokaryotes contain that not all do

(5 answers)

A
  • Slime coat
  • Flagella
  • Photosynthetic pigments
  • Mesosome (possible site of respiration)
  • Plasmids
52
Q

Deffine Tissue

A

A group of layers of similar cells working together to perform a specific function

53
Q

Define an Organ

A

A collection of different tissues working together to perform a specific function

54
Q

Name 3 examples of tissues found in the human body

A
  1. Epithelial Tissue
  2. Muscle Tissue
  3. Connective Tissue
55
Q

Describe the structure of epithelial tissues

A
  • cells packed closely together
  • rest on the basement membrane
56
Q

What is the function of epithelial tissues

A
  • Lining tissue that covers the surface of organs, cavities and tubes
  • Protect cells underneath
  • Secrete substances
  • Absorb substances
  • Excrete waste products
57
Q

Describe the structure of squamous epithelial tissue

A

Flattened cells on a basement membrane

58
Q

What is the function of squamous epithelial tissue

A
  • Form the walls of the alveoli
  • Line Arteries, veins & Capilliaries
59
Q

What is the structure of cuboidal epithelial tissue

A

Box shaped cells that are 1 cell thick

60
Q

What is the function of cuboidal epithelial tissue

A

Involved with secretion and absorption

61
Q

Where is cuboidal epithelial tissue found

A
  • Kidney tubules
  • Glandular ducts
62
Q

Where is cuboidal epithelial tissue found

A
  • Kidney tubules
  • Glandular ducts
63
Q

What is the structure of columnar epithelial tissue

A
  • column shaped cells
  • some have cilia and some have microvilli
64
Q

What is the function of columnar epithelial tissue

A
  • Cilia waft dust & dirt trapped in mucus out of air passages
  • Microvilli increase the surface area
65
Q

Where is columnar epithelial tissue found

A
  • Found in the trachea and bronchi with cilia.
  • Found in the small intestine with microvilli
66
Q

What is the structure of glandular epithelial tissue

A

Contain mucus secreting goblet cells

67
Q

What is the function of glandular epithelial tissue

A

Secrete enzymes, hormones, salive etc.

68
Q

Where is glandular epithelial tissue found

A
  • Digestive system
  • Pancreas
  • Salivary gland
69
Q

What is the structure of connective tissue

A
  • Contains elastic and collagen fibres in an extracellular fluid / matrix
  • Between fibres are fat-storing adipocytes and immune system cells
70
Q

What is the function of connective tissue

A
  • To support or separate tissues and organs
71
Q

What is the structure of skeletal muscle

A
  • Muscle cells are joined together to form fibres
  • Striations are caused by overlapping of protein molecules in cell
  • Attached to bones by tendons
72
Q

What is the function of skeletal muscle

A
  • Voluntary movement
  • Skeletal movement
  • Maintain posture and body position
  • Support soft tissue
73
Q

What is the structure of smooth muscle

A

Unstriated, individual cells that can shorten in length

74
Q

What is the function of smooth muscle

A
  • involuntary contractions e.g to move things around the body
75
Q

Where is smooth muscle found

A
  • Skin
  • Walls of blood vessels
  • Digestive tract
  • Respiratory tract
76
Q

What is the structure of cardiac muscle

A
  • Striated and branched fibres
  • Attatched at ends to adjoining fibres by thick plasma membranes called intercallated disks
77
Q

What is the function of cardiac muscle

A

Rhythmic contraction to pump blood through the heart