Cell and its organelles Flashcards
1
Q
What is histology?
A
The study of cellular structures of the body
2
Q
What is a cell?
A
Basic morphological unit and functional unit of all living things
3
Q
How are cells that perform the same functions connected?
A
Linked together by intracellular materials or via cell-to-cell junction to form tissues
4
Q
What do tissues bond together to form?
A
More complex functional structures called organs (e.g., stomach, lungs, heart)
5
Q
What are organ systems?
A
Groups of organs that have interrelated functions (e.g., Respiratory system: lungs, larynx, pharynx)
6
Q
How many cells are approximately in the human body?
A
Approximately 1014 or 100 trillion cells
7
Q
How many different cell types do we have in the body?
A
200+ cell types
8
Q
What is the key to identifying cell types?
A
Observation using microscopy
9
Q
Who discovered the cell and when?
A
Robert Hooke in 1665
10
Q
What did Robert Hooke observe?
A
A plant cell under a light microscope (cork cell)
11
Q
Who is known for identifying multiple protozoa and bacteria?
A
Anton Van Leewenhoek in 1673
12
Q
What is significant about Anton Van Leewenhoek’s observations?
A
He observed living cells
13
Q
What work did Anton Van Leewenhoek author?
A
Micrographia
14
Q
Who discovered the nucleus and when?
A
Robert Brown in 1833
15
Q
What did Felix Dujardin discover?
A
Fluid content of the cell
16
Q
What did Matthias Schleiden propose?
A
All plants are made up of cells (1839)
17
Q
Who named the fluid content of the cell protoplasm?
A
J.E Purkinje
18
Q
What did Theodore Schwann propose?
A
All animals are made up of cells
19
Q
Who proposed that the cell is the basic unit of life?
A
Carl Heinrich Braun
20
Q
What did Rudolf Virchow propose?
A
All cells arise from pre-existing cells
21
Q
What is a unicellular organism?
A
An organism that is made up of only one cell
Examples include Euglena, Paramecium, and Yeast.
22
Q
What is a multicellular organism?
A
An organism that is made up of more than one cell
Examples include Plants, Animals, and Fungus.
23
Q
What unit is used to measure the size of cells?
A
Micrometer (μm)
24
Q
What is the size of Mycoplasma?
A
0.1μm
Mycoplasma is the smallest cell known to human.
25
What is the size of an ostrich egg, the largest cell?
18cm
26
What are the basic structures of cells?
* Cytoplasm
* Enclosed in a Cell Membrane
* Nucleus enclosed in a Nuclear Envelope embedded in the Cytoplasm
27
What is the size of a sperm cell?
5μm
## Footnote
Sperm cell is the smallest cell in humans.
28
What is the size of an ovum cell?
120μm
## Footnote
Ovum cell is the largest cell in humans.
29
What is the longest cell in humans?
Nerve Cell
## Footnote
Nerve cells can be up to 1 meter long.
30
How do human red blood cells (RBCs) appear?
Circular biconcave
## Footnote
This shape aids in easier passage through human capillaries.
31
What is the shape of nerve cells?
Branched
## Footnote
This shape helps conduct impulses from one point to another.
32
How can human white blood cells (WBCs) change?
They can change their shape
## Footnote
This ability allows them to engulf foreign microorganisms through phagocytosis.
33
Cells can vary in size. True or False?
True
34
Cells can vary in shape. True or False?
True
35
Fill in the blank: The smallest cell known to humans is _______.
Mycoplasma
36
Fill in the blank: The largest cell is an _______.
ostrich egg
37
What type of microscope allows for a magnification of 2000x?
Compound Microscope
## Footnote
A compound microscope is commonly used for studying cell structures.
38
What is the magnification capability of an electron microscope?
500,000x
## Footnote
An electron microscope provides much higher magnification than a compound microscope.
39
What term describes the structure of a cell as seen under an electron microscope?
Ultrastructure
## Footnote
Ultrastructure refers to the detailed structure of cells observed with high magnification.
40
What are the distinguishing features of an animal cell?
* Generally small in size
* Cell wall is absent
* Plastids are absent
* Vacuoles are smaller and fewer
* Centrioles are present
41
What are the distinguishing features of a plant cell?
* Generally large in size
* Cell wall is present
* Plastids are present
* Vacuoles are larger and more numerous
* Centrioles are absent
42
What does the cell theory state?
* All living things are made up of cells
* Cells are the smallest working units of all living things
* All cells come from preexisting cells through cell division
43
What is the smallest unit capable of performing life functions?
Cell
## Footnote
Cells are fundamental units of life.
44
What are the two main types of cells?
* Prokaryotic
* Eukaryotic
45
Which type of cell has an underdeveloped nucleus?
Prokaryotic
## Footnote
Prokaryotic cells typically have a simpler structure compared to eukaryotic cells.
46
What is a characteristic of prokaryotic cells regarding chromosomes?
Only one chromosome is present
47
What is absent in prokaryotic cells?
Membrane-bound organelles
48
What is the size range of prokaryotic cells?
0.5 − 5μm
49
Provide an example of a prokaryotic organism.
Bacteria and Blue-green algae
50
What defines a eukaryotic cell?
* Nucleus is well developed
* More than one chromosome is present
* Membrane-bound organelles are present
51
What is the size range of eukaryotic cells?
5 − 100μm
52
Provide an example of a eukaryotic organism.
All other organisms
53
True or False: Prokaryotic cells contain organelles surrounded by membranes.
False
54
True or False: Eukaryotic cells are mostly single-celled organisms.
False
55
Fill in the blank: The smallest unit that is capable of performing life functions is called a _______.
Cell
56
What is the primary function of the cell wall?
Protection, structure, regulation, filtering
## Footnote
The cell wall supports and protects cells, helps maintain shape, regulates information flow, and acts as a selective barrier.
57
What is the composition of the cell wall?
Cellulose, hemicellulose, pectin
## Footnote
The cell wall can be tough, rigid, and sometimes flexible.
58
What type of cells commonly have a cell wall?
Plant cells, bacteria
## Footnote
The cell wall is found in most plant cells and bacteria.
59
What is the plasma membrane's main characteristic?
Semi-permeable
## Footnote
The plasma membrane allows certain substances to pass while blocking others.
60
What is the primary structure of the plasma membrane?
Two layers of lipid molecules with floating protein molecules
## Footnote
The plasma membrane is extremely delicate and can only be observed under an electron microscope.
61
What are the main functions of the nucleus?
Directs cell activities, stores genetic material, synthesizes RNA
## Footnote
The nucleus is the control center of the cell, containing DNA and directing metabolism and growth.
62
What is the nucleolus responsible for?
Synthesis of ribonucleic acid (RNA)
## Footnote
The nucleolus manufactures subunits that combine to form ribosomes.
63
What is the nuclear envelope?
A double-layered membrane surrounding the nucleus
## Footnote
It has an outer and inner layer separated by a fluid-filled space.
64
What are chromosomes made of?
DNA and nucleoproteins
## Footnote
Chromosomes contain genetic instructions for traits and characteristics.
65
How many chromosomes are present in the human body?
46 chromosomes
## Footnote
This includes 22 pairs of somatic chromosomes and 1 pair of sex chromosomes (X and Y).
66
What distinguishes euchromatin from heterochromatin?
Euchromatin is light staining and active, heterochromatin is darkly staining and non-active
## Footnote
Euchromatin indicates active transcription, while heterochromatin is tightly coiled and not transcriptionally active.
67
What is the cytoplasm composed of?
80% water, cytosol, and various particles
## Footnote
The cytoplasm is the site for biochemical processes and provides a suitable environment for organelles.
68
Name three types of membranous organelles.
* Mitochondria
* Endoplasmic Reticulum
* Golgi apparatus
## Footnote
Other membranous organelles include lysosomes, peroxisomes, and centrosomes.
69
What is the role of the nuclear membrane?
Surrounds the nucleus and regulates exchange of substances
## Footnote
The nuclear membrane has pores that allow materials to enter and leave the nucleus.
70
Fill in the blank: The _______ synthesizes ribosomal RNA.
Nucleolus
## Footnote
The nucleolus is crucial for the formation of ribosomes.
71
True or False: The nucleus is present in all cells.
False
## Footnote
The nucleus is absent in red blood cells and sieve tube cells.
72
What is nucleoplasm?
Colorless dense sap inside the nucleus
## Footnote
Nucleoplasm contains the nucleolus and chromatin fibers.
73
What are the two distinct dispersal patterns of chromatin?
* Euchromatin
* Heterochromatin
## Footnote
Euchromatin is less coiled and active, while heterochromatin is tightly coiled and inactive.
74
What is the function of ribosomes?
Assemble amino acids into proteins
## Footnote
Ribosomes are essential for protein synthesis.
75
What is the primary function of mitochondria?
Produces energy through chemical reactions – breaking down fats & carbohydrates
## Footnote
Mitochondria are often referred to as the powerhouse of the cell.
76
What metabolic process occurs in mitochondria?
Krebs cycle generates ATP (energy)
## Footnote
The Krebs cycle is a key component of cellular respiration.
77
What is the typical shape of mitochondria?
Often 'hotdog' shape but may vary to rod-like, filamentous, or spherical
## Footnote
The shape depends on the cell's activity.
78
What is the size range for mitochondria?
Usually 0.5 − 1μm in diameter and up to 10μm long
79
What type of microscopy can be used to view mitochondria?
Phase-contrast microscopy and electron microscopy using Janus Green
## Footnote
Janus Green is a special stain used for visualization.
80
What are the two membranes surrounding mitochondria called?
Inner membrane and outer membrane
## Footnote
The outer membrane is smooth and encloses the mitochondrial contents.
81
What are the inward projections in the inner membrane of mitochondria called?
Cristae (cristae mitochondriales)
82
How do mitochondria replicate?
Via binary fission
83
From where do all mitochondria in the body originate?
From the female ovum
## Footnote
Sperm does not contribute to the cytoplasmic component of the zygote.
84
What does the inner cavity of mitochondria contain?
A matrix that contains many enzymes
85
What is the function of ATP in cells?
Provides energy for the vital activities of living cells
86
What is the primary role of the endoplasmic reticulum?
Moves materials around in the cell
87
What are the two types of endoplasmic reticulum?
Smooth type and rough type
## Footnote
Rough type has ribosomes, while smooth type lacks them.
88
What is the function of the smooth endoplasmic reticulum (SER) in liver cells?
Detoxifies drugs and poisons
89
What type of proteins does the rough endoplasmic reticulum (RER) synthesize?
Secretory proteins and membrane proteins
90
What are ribosomes responsible for?
Synthesize proteins by translating mRNA into amino acids
91
What are polyribosomes?
Clusters of ribosomes linked by mRNA that they are currently translating
92
How do ribosomes produce proteins?
1. Cell nucleus transcribes DNA into RNA
2. mRNA is transported to the cytoplasm
3. Ribosomes bind to mRNA and read genetic code
4. Ribosomes link amino acids together in order specified by mRNA
5. Amino acids grow into long chains called polypeptides
6. Polypeptides fold into proteins
93
What is the role of the Golgi body?
Protein 'packaging plant' that modifies and transports proteins within the cell
94
What are the two ends of the Golgi body called?
Cis face and trans face
## Footnote
Cis face is near the endoplasmic reticulum, while the trans face is near the cell membrane.
95
What is the function of lysosomes?
Digestive 'plant' for proteins, fats, and carbohydrates
96
What happens if a lysosome explodes?
The cell breaks down
## Footnote
This is referred to as a suicide sac.
97
What is the pH level of lysosomes for acid hydrolase activity?
5
98
What are the functions of vacuoles?
* Storage
* Transport
* Waste management
* Intracellular stability
* Cell shape
* Cell protection
99
How do vacuoles differ in plant cells compared to animal cells?
In plant cells, vacuoles are large and more numerous; in animal cells, they are temporary, small, and few in number
100
What are the two types of non-membranous organelles?
microtubules, microfilaments
## Footnote
Non-membranous organelles include structures that do not have a surrounding membrane.
101
What is the structure of a centrosome?
Consists of two structures called centrioles
## Footnote
Centrosomes are membrane-bound organelles located near the nucleus.
102
What are centrioles?
Hollow, cylindrical structures made of microtubules
## Footnote
Centrioles are found inside the centrosomes and are arranged at right angles to each other.
103
What is the function of spindle fibers?
Help in the movement of chromosomes during cell division
## Footnote
Spindle fibers grow out from centrosomes during mitosis.
104
What protein makes up microtubules?
tubulin
## Footnote
Microtubules are hollow tubules that play a critical role in maintaining cell structure.
105
What are microfilaments made of?
actin
## Footnote
Microfilaments are rod-shaped thin filaments that contribute to the cell's structural integrity.
106
List the functions of the cytoskeleton.
* Determine the shape and internal organization of the cell
* Give structural strength to the cell
* Provide mechanical support for essential functions
* Responsible for cellular movements
## Footnote
The cytoskeleton is crucial for maintaining the cell's shape and facilitating movement.
107
What are cellular inclusions?
Secretory Granules, Vesicles, Pigment granules, Lipid droplets, Glycogen, Crystalline Particles
## Footnote
Cellular inclusions are various substances stored within cells.
108
How are centrioles arranged?
At right angles to each other
## Footnote
Centrioles are built from a cylindrical array of 9 microtubules.
109
What happens to centrosomes before mitosis?
They move apart until they are on opposite sides of the nucleus
## Footnote
This movement is essential for proper chromosome segregation.
110
Fill in the blank: Microtubules are made up of a protein called _______.
tubulin
## Footnote
Microtubules are key components of the cytoskeleton.
111
True or False: The cytoskeleton is involved in cellular movements.
True
## Footnote
The cytoskeleton provides the necessary structure for cell motility.
