Cell : The Unit of Life Flashcards
1
Q
In living things, growth is _____.
In non-living things, growth is _____.
A
- Intrinsic
2. Extrinsic
2
Q
Who first saw and described a live cell?
A
Anton Von Leeuwenhoek
3
Q
Who discovered the nucleus?
A
Robert Brown
4
Q
Who discovered plasma membrane and cell wall?
A
Theodore Schwann
5
Q
Which scientist observed that cells are made of different cells which form tissues?
A
Matthias Schleiden
6
Q
“Life always arises from pre-existing cells.”
Which two scientists stated this?
Write its original statement.
A
Rudolf Virchow and Louis Pasteur.
Omnis cellula-e cellula.
7
Q
Who formulated the cell theory?
State its postulates. (2)
A
Schleiden and Schwann.
(i) all living organisms are composed of cells and products of cells.
(ii) all cells arise from pre-existing cells.
8
Q
Drawbacks of cell theory. (3)
A
- Never explained the division of a cell.
- Ribosomes have no membrane.
- RBCs and viruses don’t reproduce.
9
Q
Characteristics of a prokaryotic cell. (3)
A
- Don’t have a membrane-bound nucleus
- Have 70S ribosome in cytoplasm.
- Monerans
10
Q
Characteristics of a eukaryotic cell. (3)
A
- Have a membrane-bound nucleus
- Have 80S ribosome in the cytoplasm, mitochondria, rough ER, chloroplasts (only plants).
- Starts from Protista
11
Q
State the lengths of:
- Mycoplasma
- Bacteria
- RBC
A
- 3 micrometer
- 3-5 micrometer
- 7 micrometer
12
Q
Cell vary in shape with respect to _______.
A
Their Functions
13
Q
RBCs are ________ in mammals and amphibians but _______ in other animals.
A
- Biconcave
2. Round
14
Q
WBCs are _____. Their movement is called _____.
A
- Amoeboid
2. Diapedesis
15
Q
Name:
- The largest isolated single cell.
- Longest cell.
A
- Ostrich egg
2. Nerve cell
16
Q
Another name for blue-green algae.
A
Cyanobacteria
17
Q
Why is cyanobacteria a drawback of the 5-kingdom classification?
Write its major characteristic.
A
Because it is algae but is still included in Monera.
It is an oxygenic autotroph.
18
Q
Full form of PPLO.
How was PPLO discovered?
Write its characteristics. (2)
A
Pleuro Pneumonia-like Organisms.
Discovered it when a cow got pneumonia.
They are smaller and multiply faster than eukaryotic cells.
19
Q
What are the four basic shapes of bacteria?
A
- Bacillus - rod
- Coccus - sphere
- Vibrio - comma
- Spirillium - spiral
20
Q
Write the size of:
- Eukaryotic cell
- Bacteria
- PPLO
- Virus
A
- 10-20 micrometer
- 1-2 micrometer
- 0.1 micrometer
- 0.02-0.2 micrometer
21
Q
All prokaryotes have cell walls, except _____.
A
Mycoplasma
22
Q
The genetic material in prokaryotes is naked. This means that ______.
A
There are no histone proteins.
23
Q
Write characteristics of Genomic DNA (2) and Circular DNA (4).
A
Genomic DNA
- Also called Housekeeping DNA.
- Essential, controls vital activity.
Circular DNA
- Also called a plasmid.
- It is extra non-essential.
- Confers phenotypic characters to bacteria, eg. resistance to antibiotics.
- Used to monitor bacterial transformation with foreign DNA.
24
Q
Two unique organelles in prokaryotes are?
A
- Inclusion
2. Mesosomes
25
Define Transformation.
Introduction of vector DNA to host cell.
26
What are the three layers of the cell envelope in prokaryotes?
What is the function of the cell envelope?
1. Glycocalyx
2. Cell wall
3. Plasma membrane
Function - Protection
27
Who developed the staining procedure of bacteria?
Those that take up the stain are _____. Those who don't take up the stain are ______.
_______ don't take up stain because they have a _______.
1. Gram
2. Gram-positive, Gram-negative
3. Gram-negative, lipid layer
28
What are the two types of glycocalyx?
1. Slime layer - loose sheath
| 2. Capsule - thick and tough
29
What is the cell wall in bacteria made of?
| What are its functions?
1. Cell wall is made of a heteropolysaccharide called Peptidoglycan. It is made of N-acetyl glucose amine (NAq) and N-acetyl muramic acid (NAM).
2. It determines the shape of a cell and strong structural support to prevent bursting/collapsing.
30
What is the Bactrian plasma membrane made of?
| State its function.
1. Lipid bilayer (like eukaryotes)
| 2. selectively permeable, interactive
31
Describe mesosomes.
What are its three forms?
What are its functions?
1. They are extensions of the plasma membrane.
2. Vesicles, tubules, lamellae
3. a. Cell wall formation, DNA replication, distribution to daughter cells.
3. b. Respiration, secretion, increase the surface area of plasma membrane and enzymatic content.
32
Membranous extensions in cyanobacteria are called ______.
| They contain _______.
1. Chromatophores
| 2. pigments
33
_______ is a thin filamentous extension in bacteria.
It is an extension of ________.
Its main function is _______.
1. Flagella
2. cell wall
3. motility
34
What are the three parts of the bacterial flagellum?
Filament, Hook and Basal body
35
What are bacterial pili made of?
State their function.
How are fimbriae useful to the bacteria?
1. Pilin protein
2. Reproduction
3. Adhesion
36
In prokaryotes,
1. Ribosomes are associated with?
2. Their size is?
1. Plasma membrane
| 2. 15-20 nm
37
1. Ribosomes are a site of ________.
2. Several ribosomes may attach to a single ______ and form a chain called _______ or ________.
3. Ribosomes of a polysome translate ______ into _______.
1. Protein synthesis
2. mRNA, polyribosome or polysome.
3. mRNA, proteins
38
1.Reserve material in prokaryotic cells are stored in ______ in the form of _______.
They are not bound by any membrane system.
2. State 3 substances that they store.
1. cytoplasm, inclusion bodies
2. Phosphate granules
Cyanophycean granules
Glycogen granules
39
1. Gas vacuoles provide _______.
| 2. Gas vacuoles are found in _______, _______ and ______ photosynthetic bacteria.
1. Buoyancy
| 2. Blue-green, purple, green
40
Cytoskeletal structures of eukaryotic cells are made of _____ and ______.
proteins, microtubules
41
1. Genetic material of eukaryotic cells is organized into ________.
2. Configuration of the nucleus is _____.
1. chromosomes
| 2. 2n
42
Plant cells consist of _______ in the cell wall.
B-cellulose (beta)
43
Centrioles help animal cells in ______.
cell division
44
1. Nucleolus produces _______.
| 2. Peroxisome produces ______.
1. rRNA - ribosomal RNA
| 2. Peroxidases
45
_________ is a cytoplasmic cell junction that allows ______ water movement.
Plasmodesmata, symplastic
46
The lysosome is called a suicidal bag. Why?
The high acidic content bag that burst when a cell is damaged beyond repair.
47
Packaging of vesicles in plant cells is done by ______.
Dictyosomes
48
In chloroplast, chlorophyll is present in ______ membrane.
thylakoid
49
Microvilli _____ surface area of absorption.
| It is present mainly in _____ and _____.
1. increase
| 2. small intestine, PCT
50
The centriole is at ____ angle in a cell.
90, right angle
51
Why were RBCs used to study plasma membrane?
Because RBCs are hollow, have no organelles inside.
| Easier to study plasma membranes.
52
Plasma membrane consists of _____ arranged in a bilayer.
Polar heads are _______ and hydrophobic tail is ______.
Lipid component of membrane consists mainly of ________.
1. phospholipids
2. outside, inside
3. phosphoglycerides
53
In addition to phospholipids, membrane also consists of _______.
It provides _____ to the plasma membrane.
Cholesterol
| Fluidity
54
Cholesterol is formed from _______ in the _____.
| It is of two types. What are they?
1. acetic acid, liver
2. LDL - low-density lipoprotein
HDL - high-density lipoprotein
55
Why is LDL cholesterol considered dangerous?
It causes atherosclerosis and coronary artery diseases.
56
In human beings, the erythrocyte membrane has approx ___% protein and ___% lipids.
52, 40
57
Depending on the ease of extraction, membrane proteins are divided into ______ and _______.
Integral and Peripheral proteins
58
The phospholipid layer consists of which two parts?
1. Hydrophilic phosphate
| 2. Hydrophobic lipid
59
________ is present on the surface of the plasma membrane.
| It is a receptor for ______.
1. Peripheral protein
| 2. water-soluble hormone
60
An improved model of the structure of cell membrane was proposed by ______ and _______ (1972) widely accepted as the ________.
Singer and Nicolson
| Fluid mosaic model
61
The ability of proteins to move within the membrane is measured as its _______.
What are the two types of movements?
1. fluidity
2. Lateral- along the same membrane
Flip-flop- between different membranes
62
Why is fluidity important for membranes? (5)
1. cell growth
2. formation of intercellular junctions
3. secretion
4. endocytosis
5. cell division
63
1. Intake of food by a cell is called ______.
2. Intake of liquids by a cell is called ______.
3. Exiting waste by a cell is called ______.
1. Endocytosis
2. Pinocytosis
3. Exocytosis
64
What are passive transport, osmosis and active transport in context to plasma membrane?
1. Passive Transport
Molecules move briefly across a membrane without using energy.
2. Osmosis
Movement of water molecules from higher to lower concentration via semi-permeable plasma membrane
3. Active Transport
Energy-dependent process of facilitated transport from lower to higher concentration (uses ATP)
65
As the polar molecules cannot pass through the nonpolar lipid bilayer, they require a ________ to move.
Give an example of active transport.
1. carrier protein
| 2. Na+/K+ pump
66
The bridge between two cell-wall cells is called _________.
plasmodesmata
67
The cell wall forms an outer covering for the plasma membrane of _____ and ______.
fungi and plants
68
State functions of the cell wall. (4)
1. Gives shape to the cell
2. Protects the cell from mechanical damage and infection
3. It also helps in cell-to-cell interaction
4. Provides a barrier to undesirable macromolecules
69
What is an algae cell wall made of?
| What is a plant cell wall made of?
1. cellulose, galactans, mannans and minerals like calcium carbonate
2. cellulose, hemicellulose, pectins and proteins.
70
The cell wall of a young plant cell, the _______ is capable of growth.
It gradually diminishes as the cell matures and the ________ is formed on the _______ side of the cell.
1. primary wall
| 2. secondary wall, inner (towards membrane)
71
The middle lamella is a layer mainly of __________ which holds or glues the different neighbouring cells together.
calcium pectate
72
The cell wall and middle lamellae may be traversed by _________ which connect the cytoplasm of neighbouring cells.
plasmodesmata
73
In the primary wall, cellulose is _____ than hemicellulose.
In the secondary wall, cellulose is ______ than hemicellulose.
It doesn't support ______.
1. less
| 2. more, growth
74
Which organelles does the endomembrane system consist of?
Endoplasmic reticulum (ER)
Golgi complex
Lysosomes
Vacuoles.
75
ER divides the intracellular space into two distinct compartments, ________ and ________ compartments.
```
luminal (inside ER)
extra luminal (cytoplasm)
```
76
What is the sarcoplasmic reticulum (SR)?
Endoplasmic reticulum in the cytoplasm of muscle cells
77
What is the function of RER and SER?
1. RER - protein synthesis and secretion.
2. SER - synthesis of lipid. In animal cells lipid-like
steroidal hormones are synthesised in SER.
78
What are steroidal hormones? Give 6 names.
Hormones derived from cholesterol
Androgens, estrogen, progesterone, testosterone, cortisol, aldosterone
79
1. Who first observed Golgi bodies in 1898?
| 2. Describe their appearance and position.
1. Camillo Golgi
2. They consist of many flat, disc-shaped sacs or
cisternae of 0.5µm to 1.0µm diameter.
These are stacked parallel to each other.
Only observed when densely stained.
80
The Golgi cisternae are concentrically arranged near the nucleus with distinct _______ or the forming face and ________ or the maturing face.
They are interconnected.
convex cis
| concave trans
81
Materials to be packaged in the form of vesicles from the ER fuse with the ______ face and move towards the ______ face.
cis, trans
82
What are the functions of Golgi bodies?
1. Packaging materials to be released/secreted
2. Formation of glycoproteins and glycolipids
(glycosylation)
3. Formation of lysosomes by packaging
83
How are proteins synthesised in ribosomes released in the cell?
Modified in the cisternae of the Golgi apparatus before they are released from its trans face.
84
1. What are lysosomes rich in?
| 2. Those enzymes are capable of?
1. Lysosomal vesicles are rich in almost all types of hydrolytic enzymes.
(hydrolases –lipases, proteases, carbohydrases)
2. Optimally active at the acidic pH.
Capable of digesting carbohydrates, proteins, lipids and nucleic acids.
85
1. The vacuole is bound by a single membrane called _______.
| 2. What is its function?
1. Tonoplast
| 2. Facilitates transport of materials against concentration gradients into the vacuole
86
1. In plant cells the vacuoles can occupy up to ___% of the volume of the cell.
2. Concentration is ______ in the vacuole than in the cytoplasm.
1. 90%
| 2. higher (more)
87
In sperms, Golgi bodies contain ______ that synthesise proteolytic and hydrolytic enzymes.
acrosome
88
1. In Amoeba the contractile vacuole is important for _______ and ________.
2. In entamoeba, contractile vacuole is ______.
1. osmoregulation, excretion
| 2. absent
89
1. The number of mitochondria per cell is variable depending on?
2. Red muscle has _____ mitochondria than white muscles.
3. What kind of respiration do the above muscles perform?
1. physiological activity of cell
2. more
3. red - aerobic
white - anaerobic
90
1. The mitochondrial outer membrane is ______ permeable than the inner membrane.
2. ______ cycle occurs in mitochondria.
1. less
| 2. Krebbs
91
1. The inner compartment is filled with a dense homogeneous substance called the ______.
2. The inner membrane forms a number of infoldings called the _______ towards the matrix.
3. Mitochondria are the sites of _______ respiration. They produce cellular energy in the form of _____.
4. The mitochondria divide by ______.
1. matrix
2. cristae
3. aerobic, ATP
4. fission
92
1. What components does the matrix have?
| 2. Mitochondria is an _______.
1. single circular DNA molecule
few RNA molecules
ribosomes (70S)
components required for the synthesis of proteins.
2. endosymbiont
