Cell Structure and Function Flashcards

1
Q

Definition of prokaryote

A

DNA of the cell is not separated from the cytoplasm

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2
Q

Definition of eukaryote

A

DNA is partitioned off in a membrane bound nucleus

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3
Q

Compare the characteristics of prokaryotic and eukaryotic cells

A
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4
Q

Properties of the plasma membrane

A
  1. Surrounds the cell
  2. Partially permeable
  3. Highly permeable to water and oxygen
  4. Charged ions do not pass through easily
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5
Q

Components of the cell membrane

A
  1. Phospholipids
  2. Protein
  3. Carbohydrates
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6
Q

Function of the protein component of the cell membrane

A

Pass ions into and out of the cell
Receptors

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7
Q

Structure of carbohydrate component of the cell membrane

A

Attached to proteins as glycoproteins or attached to lipids as glycolipids

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8
Q

Functions of carbohydrate molecules in cell membrane

A

Cell-cell recognition
Communication
Intercellular adhesion

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9
Q

Methods of transporting large molecules across plasma membrane

A

Exocytosis
Endocytosis (including pinocytosis and phagocytosis)

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10
Q

Define exocytosis

A

Release of material from the cell cytoplasm across the cell membrane

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11
Q

Define endocytosis

A

Uptake and transfer of molecules across the cell membrane into the cell interior

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12
Q

Define pinocytosis

A

Cells ingest small molecules of extracellular liquids

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13
Q

Define phagocytosis

A

Ingestion of large solid particles by the cells, e.g. bacteria

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14
Q

What is the endoplasmic reticulum?

A

A network of interconnected tubules & vesicles

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15
Q

What are the types of endoplasmic reticulum?

A

Rough Endoplasmic Reticulum
Smooth Endoplasmic Reticulum

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16
Q

Characteristics of the rough ER

A

Studded with ribosomes
Synthesizes proteins

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17
Q

Characteristics of smooth ER

A

Lacks ribosomes
Segregates newly synthesized proteins from the cytoplasm
Detoxification of drugs in the liver
Lipid synthesis (in gonads, adrenal gland)
Ca2+ reservoir in skeletal muscle

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18
Q

What are ribosomes formed from?

A

Made from 2 subunits formed from proteins

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19
Q

Where can ribosomes be found?

A

In the rough ER
Free in the cytoplasm

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20
Q

Functions of ribosomes

A

Translate mRNA into proteins

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21
Q

What are polyribosomes?

A

Clusters of ribosomes held together by strand of mRNA

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22
Q

What is the Golgi Apparatus?

A

Stacked and flattened membranous sacs which are closely associated with the rER

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23
Q

Shape of the Golgi Apparatus

A

Concave side (cis side): Near the ER
Convex side (tras side)

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24
Q

Function of the Golgi Apparatus

A

Modifies, packages and transports proteins and lipids secreted by the cells

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25
Q

What is the function of lysosomes?

A

Break down waste materials and cellular debris

26
Q

How are lysosomes formed?

A

Vesicles produced by the Golgi Apparatus

27
Q

What do lysosomes contain?

A

Acid hydrolases

28
Q

What are phagosomes?

A

Vacuole that is formed by the fusion of the cell membrane around the particle

29
Q

What are peroxisomes?

A

Membrane-bound organelles
Present in all cells but prominent in hepatocytes and proximal tubule cells
Contain oxidative enzymes

30
Q

What are the functions of peroxisomes?

A

Hydrogen Peroxide Metabolism
Fatty acid metabolism
Alcohol degradation
Formation of phospholipid needed for myelination of nerve cells

31
Q

What are mitochondria?

A

Oval or elongated structures which vary in number according to the cell function

32
Q

What is the structure of the mitochondria?

A

Contain an outer and inner membrane
Inner membrane is folded into cristae
Contains granular material called matrix

33
Q

What are the functions of the mitochondria?

A

Generation of ATP
Control cell cycle and cell growth
Apoptosis

34
Q

What is the nucleus?

A

Membrane bound organelle containing chromatin, nucleoli and surrounded by nuclear envelope

35
Q

What is the nuclear envelope?

A

Double layered membrane forming a selective barrier bewteen the cytoplasm and nucleus

36
Q

Outer membrane of the nuclear envelope is continuous with …

A

Rough endoplasmic reticulum

37
Q

What is the inner nuclear membrane lined with?

A

Nuclear lamina (condensation of intermediate filaments)

38
Q

What is the function of the nuclear lamina?

A

Maintain the shape of the nucleus

39
Q

How are nuclear pores formed?

A

Fusion of the outer and inner membrane of the nuclear envelope

40
Q

Function of the nuclear pores

A

Control the movement of ribosomal subunits between the nucleus and cytoplasm

41
Q

Function of chromatin

A

Encodes cell structure and function

42
Q

Types of chromatin

A

Heterochromatin: Darkly staining and inactive
Euchromatin: Lightly staining and active

43
Q

Characteristics of the nucleolus

A

Dark-staining spherical body
Not bound by a membrane
Contains lots of RNA and protein
Site of ribosome synthesis

44
Q

Types of cytoskeletal structures divided according to thickness

A

Microtubules (composed of tubulin subunits): 25 nm thick
Intermediate filaments: 10 nm thick
Microfilaments (mostly actin): 7 nm thick

45
Q

What are microtubules?

A

Hollow tubes responsible for intracellular movement of cytoplasmic organelles

46
Q

What are microtubules formed from?

A

Spherical protein tubulin

47
Q

What structures are formed from microtubules?

A

Centrioles
Cilia
Flagella

48
Q

Which cells do not contain microtubules?

A

RBCs

49
Q

What are intermediate filaments?

A

Tough, insoluble protein fibers with high tensile strength

50
Q

Function of intermediate filaments

A

Resist pulling forces on the cell

51
Q

What are microfilaments?

A

Strands of actin protein
Attached to the cytoplasmic side of the plasma membrane

52
Q

Function of microfilaments?

A

Braces and strengthens the cell surface

53
Q

What is the centrosome?

A

Area of the cytoplasm near the nucleus containing two small cylindrical structures called centrioles

54
Q

What are centrioles?

A

Small barrel-shaped organelles which are formed of pinwheel array of 9 triplets of microtubules

55
Q

Function of centrioles

A

Move to opposite poles of the cell during cell division
Organize spindle that controls the distribution of chromosomes to the daughter cells

56
Q

Types of cellular extensions

A

Cilia
Flagella
Microvilli
Sterocilia

57
Q

What are cilia?

A

Short cell projections composed of nine pairs of microtubules surrounding a central pair
Move fluid in a single direction across the cell surface

58
Q

What are flagella?

A

Structures longer than cilia
E.g. tail of sperm cell

59
Q

What are microvilli?

A

Tubular extensions of plasma membrane containing bundles of actin filaments
Increase surface area for absorption

60
Q

What are sterocilia?

A

Modified microvilli seen on cells in the epididymis
Length and bundle arrangement differentiate them from microvilli
Increase surface area for absorption