2B2 Cell Structures and Functions Flashcards
Identify structures and functions in prokaryotic and eukaryotic cells and differentiate between them.
1
Q
What are the main functions of a cell?
A
- Structure and support.
- Growth and repair.
- Transport of materials.
- Produce energy.
- Reproduction.
2
Q
What is a membrane-bound cell?
A
A cell surrounded by a phospholipid bilayer known as the plasma membrane.
The plasma membrane also separates the internal components of a cell and the environment.
3
Q
What are organelles?
A
Small structures that perform different jobs within a cell.
4
Q
What are membrane-bound organelles?
A
Organelles surrounded by a phospholipid bilayer.
5
Q
Which organelles are membrane-bound?
A
- Endoplasmic reticulum (both the smooth and the rough)
- Golgi apparatus
- Vacuoles
- Mitochondria
- Lysosomes (found in animal cells)
- Chloroplasts (found in plant cells)
Other organelles, that are not membrane bound include ribosomes, peroxisomes, cilia, flagella, centrioles, microtubules, cytoskeleton, centrosomes, and the cell wall.
6
Q
What type of cell arrangement is typical for prokaryotes?
A
Single-celled organisms.
Example: Bacteria, Archaea
7
Q
What is a simplified description of prokaryotic cells?
A
Simple in structure and do not contain many organelles.
8
Q
What is the average size range of prokaryotic cells?
A
0.1 - 5 micrometers in diameter.
9
Q
Do prokaryotic cells have a true membrane-bound nucleus?
A
No.
They do not have any membrane bound organelles.
10
Q
Where is the DNA located in prokaryotic cells?
A
In a space called the nucleoid.
In prokaryotic cells, the DNA is circular and resides in the nucleoid.
11
Q
Where does DNA replication and transcription take place in prokaryotic cells?
A
In the nucleoid area of the cytoplasm.
12
Q
How do prokaryotic cells divide?
A
Using binary fission.
13
Q
What specialized molecule makes up the cell walls of prokaryotic cells?
A
Peptidoglycan
A polymer of sugar and amino acids.
14
Q
What types of cells have membrane bound organelles?
A
Eukaryotic cells
15
Q
What type of cell arrangement is typical for eukaryotes?
A
Can be single-cellular or multicellular organisms.
16
Q
What is the average size range of eukaryotic cells?
A
10 - 100 micrometers in diameter.
Some eukaryotic cells are able to be seen with the naked eye. For example: chicken egg.
17
Q
What is the process of cell division in eukaryotic cells called?
A
Mitosis
18
Q
What is the main advantage of organelles in eukaryotic cells?
A
They compartmentalize cellular functions, separating processes and organizing space.
19
Q
List the similarities between prokaryotic and eukaryotic cells.
A
- Both are alive.
- Have a cell membrane.
- Contain DNA.
- Have ribosomes.
- Can divide and reproduce.
20
Q
What are some similarities between bacterial cells and eukaryotic cells?
A
- Cell wall (in some cases)
- Cell membrane
- Ribosomes
- Cytoplasm
- Genetic material
21
Q
What are the differences between prokaryotic and eukaryotic cells?
A
- Prokaryotic Cells:
- Simple structure
- Lack true nucleus
- Lack membrane-bound organelles
- Unicellular
- Reproduce through binary fission
- Eukaryotic Cells:
- Larger and more complex
- Contain diverse organelles
- Have a membrane-bound nucleus
- Can be multicellular
- Reproduce through mitosis
22
Q
What is the main difference between eukaryotic and prokaryotic cells?
A
Eukaryotic cells contain membrane-bound organelles, while prokaryotic cells do not.
23
Q
What is the genetic material found in both prokaryotic and eukaryotic cells?
A
DNA
24
Q
How is DNA structured in prokaryotic cells compared to eukaryotic cells?
A
- Prokaryotic cells have DNA in a single circular chromosome.
- Eukaryotic cells have DNA arranged into linear chromosomes.
25
How do prokaryotes and eukaryotes differ in terms of **reproduction**?
* Prokaryotes reproduce **asexually**.
* Eukaryotes are able to reproduce **sexually**.
26
What is a key feature **unique** to plant cells?
Presence of a **cell wall** for support and rigidity.
## Footnote
The cell wall surrounds the membrane of a plant cell.
27
What is the **cell wall** in plant cells composed of?
Cellulose
## Footnote
The cell wall is primarily made up of this carbohydrate.
28
What is the *function* of **chloroplasts** in a plant cell?
The site where photosynthesis occurs.
## Footnote
Responsible for photosynthesis by converting water and carbon dioxide into food for the plant..
29
What is the *structure* of **chloroplasts** in plant cells?
* Double membrane.
* Stacks of sacks known as grana.
30
What is the prominent structure found in plant cells that **occupies a large portion of the cell volume and stores water**?
Large central vacuole.
## Footnote
The vacuole helps the cell elongate as well as help with water balance within the cell and perform photosynthesis.
31
What is the main difference in **nutrition** between plant cells and animal cells?
* Plant cells are **autotrophs**.
* Animal cells are **heterotrophs**.
32
What term is used to describe organisms that can **create their own food**?
Autotroph
33
What term is used to describe organisms that must **consume something in order to get energy**?
Heterotroph
34
What are some examples of eukaryotic organisms?
* Plants
* Animals
* Fungi
35
How do prokaryotic and eukaryotic ribosomes differ?
They are both made of rRNA and proteins, but the subunits are different sizes.
## Footnote
Eukaryotic ribosomes are bigger than prokaryotic ribosomes.
36
What is the function of **flagella** in prokaryotic and eukaryotic cells?
To drive *movement*.
37
What are the **differences** in organelles between plant and animal cells?
* Plant Cells:
* Rectangular shape
* One large central vacuole
* No lysosomes
* Chloroplasts present
* Cell wall present
* Does not contain centrosomes to aid in replication.
* Animal Cells:
* Round shape
* Several small vacuoles
* Lysosomes present
* No chloroplasts
* No cell wall
* Contains centrosomes to aid in replication.
38
What is a **key difference** between plant cells and animal cells?
Plant cells have a cell walls, chloroplasts and central vacuoles. Animal cells do not.
39
List the similarities between animal cells and plant cells.
* Eukaryotic cells
* Surrounded by a cell membrane
* Contain membrane-bound organelles
* Mitochondria
* Nucleus
* Golgi Apparatus
* Endoplasmic Reticulum
* Ribosomes
40
What is a **plasma membrane**?
Also known as the cell membrane, is the thin, flexible barrier that separates the cell from the environment.
41
What does the **plasma membrane** do?
Has several important functions including:
* Protection
* Transport
* Recognition
* Cell signaling
42
What is the *main purpose* of the **plasma membrane** in both prokaryotic and eukaryotic cells?
It's a thin, flexible, **selectively permeable barrier** that protects the cell and regulates the passage of substances in and out.
43
What is the **fluid mosaic model** used to describe?
The **structure** of the plasma membrane.
## Footnote
The fluid mosaic model describes the structure of the plasma membrane as fluid due to the drifting nature of its components and mosaic due to the various macromolecules that make it up.
44
What are the *components* of the **plasma membrane**?
* Phospholipid Bilayer
* Proteins
* Carbohydrates
* Cholesterol
45
Describe the *structure* of a **phospholipid bilayer**.
Consists of **two layers of phospholipids** with a hydrophilic phosphate head attracted to water and a hydrophobic lipid tail that does not interact with water.
46
What are the **hydrophilic** parts of phospholipids in the bilayer?
The heads.
47
What are the **hydrophobic** parts of phospholipids in the bilayer?
The tails.
48
Are phospholipids **stationary** in the plasma membrane?
Lateral movement, rotation, and sometimes translocation can occur within the cell membrane.
49
What **stabilizes** the phospholipids in the plasma membrane?
Cholesterol molecules.
## Footnote
Cholesterol molecules located throughout the surface of the plasma membrane help stabilize the phospholipids and keep them in position ensuring membrane fluidity.
50
What type of **proteins** are found in the plasma membrane?
* Peripheral proteins
* Integral proteins
## Footnote
Peripheral proteins only go halfway through the membrane.
Integral proteins go entirely through the membrane.
51
What is the **main function of carbohydrates** in the plasma membrane?
Cell recognition.
52
What is the role of the plasma membrane in **cell signaling**?
Molecules attach to receptors on the surface of the cell membrane transporting signals between cells.
53
What does the plasma membrane allow to **diffuse** directly across it?
Small, nonpolar molecules, such as oxygen and carbon dioxide.
54
What provides the energy required for cellular processes within a cell?
**ATP** created through cellular respiration within the **mitochondria**.
55
What is the **function** of **mitochondria** in a cell?
Transform energy and break down stored energy.
## Footnote
Often referred to as the powerhouse of the cell.
56
What is the function of the **nucleus** in a cell?
Contains a cell's **genetic code** which provides the instructions for protein synthesis.
57
What is the function of the **nuclear membrane** in eukaryotic cells?
**Regulates transport** into and out of the nucleus and keeps the DNA safe.
58
What is the function of the **Golgi apparatus**?
To further process and package materials into secretory vesicles for transport.
## Footnote
Often referred to as the post office of the cell.
59
What is the **endoplasmic reticulum (ER)** referred to as in the cell?
The *transport system* or highway of the cell.
60
What are the *two categories* of endoplasmic reticulum (ER)?
* Smooth ER (SER)
* Rough ER (RER)
61
What is the **rough endoplasmic reticulum**?
Endoplasmic reticulum with *membrane-bound ribosomes attached.*
62
What is the **rough endoplasmic reticulum (RER)** responsible for?
Transporting properly synthesized proteins and retaining incorrectly made proteins.
63
What is the **smooth endoplasmic reticulum (SER)** responsible for?
Synthesizing, transporting, and storing lipids needed by the cell.
64
What is the function of **ribosomes** in a cell?
To read the code provided by the mRNA from the nucleus, translate it and use tools to *build it into proteins* which can be used for growth, repair, function, and propagation.
65
Where can ribosomes *be found* within the cell?
* Free in the cytoplasm.
* Bound to the endoplasmic reticulum.
* Within the mitochondria and chloroplasts.
66
What is a **ribosome**'s structure?
A cellular organelle made up of *multiple proteins and ribosomal RNA*. It contains two subunits, one large and one small, that join together during the translational process.
67
What is the function of the **smaller subunits** of ribosomes?
Decoding the messenger RNA.
68
What is the function of the **larger subunits** of ribosomes?
Formation of the peptide bonds.
69
What are the **stages** of protein synthesis in ribosomes?
1. Initiation stage
2. Elongation stage
3. Termination stage
70
What occurs during the **initiation stage** of ribosomal protein production?
mRNA binding to the smaller subunit of the ribosome and involves the release of initiation factors.
71
What occurs during the **elongation** stage of ribosomal protein production?
GTP binds with elongation factor Ef-Tu and formation of peptide bonds between amino acids.
72
What occurs during the **termination** stage of ribosomal protein production?
Recognition of termination codon by release factors RF1 and RF2, leading to the release of the peptide chain.
73
What happens to proteins synthesized by **membrane-bound ribosomes**?
Transferred to the endoplasmic reticulum and further to the Golgi apparatus for processing.
74
What is the function of **lysosomes** in a cell?
Contain digestive enzymes to *break down* excess or worn out organelles, food particles, viruses, and bacteria.
75
What structure found in animal cells acts as a *microtubule organizing center* during cell division?
Centrosome
## Footnote
The centrosome contains a pair of centrioles at right angles to each other.
76
How do larger molecules like glucose move across the plasma membrane?
They require a transport protein to be moved across the plasma membrane.
77
What process involves moving molecules into the cell through vesicles?
Endocytosis
78
What is the main function of a membrane-bound organelle?
Isolate certain chemical reactions and processes while regulating what substances enter and leave the organelle.
79
What is the function of vacuoles in both plant and animal cells?
Used as temporary storage sites for food, enzymes, water and other materials.
80
What organelles in **plant** and **animal** cells provide energy?
* Animal Cell- **Mitochondria**
* Plant Cell- **Chloroplasts**
81
What is the **cytoskeleton** in both plant and animal cells?
*A network of protein filaments* that help provide structure and support for the cell.
82
What elements create the cytoskeletal structure?
* **Microfilaments**: made of the protein actin.
* **Intermediate filaments**: made of a variety of proteins including keratin.
* **Microtubules**: made of tubulin.
83
What are **microfilaments** made of?
The protein actin twisted together to form a long chain.
84
What is the *function* of **microfilaments**?
* Keep cell shape.
* Play a crucial role in muscle cell contraction.
* Cause cell movement.
85
What is the function of **intermediate filaments**?
Anchoring organelles in place within the cell and helping anchor the cell to the environment.
86
What are **intermediate filaments** made of?
Several fibrous proteins twisted together like twine.
87
What is the function of **microtubules**?
* To provide support for the cell.
* Aid in cell division.
* Provide a route for intracellular transport.
88
What are the differences between microtubules and microfilaments?
* **Microtubules**:
* made of tubulin
* have a diameter of 25 nm
* involved in intracellular transport
* **Microfilaments**:
* made of actin
* have a diameter of 7 nm
* responsible for cellular movement
89
What are **cilia** and **flagella** made of?
Microtubules.
90
What is the **extracellular matrix**?
A complex structure of macromolecules that *keep cells together to form tissues in the body*.
91
What are the *functions* of the **extracellular matrix**?
* Contains growth factors.
* Helps control when new blood vessels should form.
* Serves as a guide for cell movement within the tissue.
* Helps create stem cells leading to the development of specialized cells.
92
What are the *components* of the extracellular matrix?
* Fibroblast cells.
* Proteoglycan proteins.
* Proteins such as collagen, laminin, fibronectin, and elastin.
93
What is the function of **fibrous proteins** in the extracellular matrix?
Provide tensile strength and *support* to tissues.
94
Name the **four principle classes** of fibrous proteins found in the extracellular matrix.
* Collagen
* Elastin
* Fibronectin
* Laminin
## Footnote
Collagen is the most abundant protein in the human body.
95
What is the function of **proteoglycans** in the extracellular matrix?
Provide resistance to compressive forces.
96
What is a **proteoglycan** composed of?
A protein core surrounded by long chains of starch-like molecules called glycosaminoglycans.
97
What type of cells are *responsible for producing and organizing the components* of the extracellular matrix in most tissues?
Fibroblasts
98
What is the main function of **fibronectin** in the extracellular matrix?
Helps position cells within the extracellular matrix, assist in cellular division and specialization.
99
What is the main function of **laminin** in the extracellular matrix?
Serves as the 'glue' between dissimilar tissues.
