Chapter 10: Cell Structure, Organelles, & Organelle Functions
Lysogenic Cycle
Phages with the lysogenic cycle are called virulent phages. Lysogenic cycle does not harm the host cell. Phage genome integrates into the host genome and is called prophage and bacteria having prophage are called lysogen. Phage genome replication occurs along with the host DNA replication. Phage genome does not completely take over the cellular mechanism of the host. Phage genome productivity is low in the lysogenic cycle. Lysogenic cycle is a time-consuming process and no progeny virus particles are produced. Lysogenic cycle sometimes transitioned into lytic cycle upon induction (such as UV light, lack of nutrients, or certain chemicals).
What is the structure and function of the central vacuole?
The central vacuole contains cell sap that is surrounded by a single layer membrane called the tonoplast. The central vacuole's main function is to maintain turgor pressure within the plant cell. This helps the plant cell to maintain its shape.
What are the cytoskeletal elements?
The cytoskeletal elements are microfilaments, intermediate filaments and microtubules. Microfilaments are made of the protein actin, intermediate filaments are made of a variety of proteins including keratin, and microtubules are made of tubulin.
What is the cytoskeleton and what is its function?
The cytoskeleton is a filamentous organelle that provides structure and support for the cell. It helps with cellular movement, intracellular transport and more.
What is endomembrane system and its function?
The endomembrane system is a network of membranes that function to modify, transport, and package proteins and lipids in the cell.
What is the function of the microfilaments and microtubules?
The function of microfilaments are to provide structure for the cell and to aid in movement. The function of microtubules are to also provide support for the cell, to aid in cell division, and to provide a route for intracellular transport.
What is the role of the stroma?
The function of the stroma is to provide volume around the different structures inside of the chloroplast for protection. The stroma is where the light-independent reaction process of photosynthesis takes place, also called the Carbon cycle. After the Carbon cycle expels glucose, this specialized sugar stays in the stroma until it is needed.
What is difference between prokaryotic and eukaryotic cell?
The main difference between prokaryotes and eukaryotes is that eukaryotes have a nucleus and membrane-bound organelles and prokaryotic cells do not.
Nucleolus
The nucleolus is an organelle found inside the nucleus. Its primary function is the synthesis of ribosomes, which will read mRNA strands during translation. (composed of proteins and bits of RNA, is not membrane bound, and is responsible for the construction of ribosomes)
What is the structure and function of the nucleus?
The nucleus is a membrane bound organelle found in eukaryotic cells that houses the chromosomes of that cell as well as the nucleolus. The nuclear membrane contains many nuclear pores, which facilitate the selective transport of molecules through the membrane.
What are the parts of the endomembrane system?
The parts of the endomembrane system include the nuclear envelope, endoplasmic reticulum, Golgi Apparatus, vesicles, lysosomes, and vacuoles. Each part has a specific function in the endomembrane system.
What do vacuoles in plant cells contain?
Vacuoles contain a number of different substances including sugars, ions, and waste products. The central vacuole contains a specialized substance called cell sap.
central vacuoles
Vacuoles have a variety of functions, including water storage and the elimination of waste products take up about 80% of cell mass can help maintain a pH of a cell
Golgi Apparatus
hollow, flat membranes, also called the Golgi Body - site where the proteins and lipids are processed by being tagged, sorted, and packaged, entrance is called the cis face while the exit is called the trans face
Endoplasmic Reticulum
hollowed out set of discs, the site where proteins are synthesized and modified
The function of the thylakoids is to
house the light-dependent reaction process of photosynthesis.
inner membrane of mitochondria
impermeable. Its function is to create more space to perform cellular respiration.
organelles
internal structures of the cell that have a specific function
NLS
large protein with a specialized amino acid sequence allowed into the nucleus through the nuclear pore (assuming credentials have been met)
three main types of RNA found in the nucleus: (created by the process of transcription)
mRNA tRNA rRNA
DNA is first converted into
mRNA by the process of transcription in the nucleus
Intermediate filaments
medium sized fibers that do not undergo remodeling. They help anchor organelles like the nucleus in place, anchor cells to each other and to the substrate
Nuclear envelope, aka the nuclear membrane, is the
membrane that surrounds the nucleus of the cell, acts as a barrier between the chromosomes and the cytoplasm, contains pores to move substances in and out of the nucleus and allow for RNA release
mRNA
messenger RNA code that can be read by thee cytoplasmic structure called the ribosome during translation
Smooth Endoplasmic Reticulum
no ribosomes on the surface, responsible for the production of lipids, carbohydrates, and hormones in the cell, connected to the rough ER
The cell is composed of _______________ which are internal structures of the cell that have a specific function
organelles
turgor pressure
pressure within the cell wall, used to maintain pressure
nuclear pores
protein lined channels that facilitate movement of materials into and out of the nucleus
nuclear lamina
provides structure to the nucleus by attaching to the nuclear envelope and chromatin.
cell walls
represents a specialized structure found in plants that specifically helps to maintain turgor pressure within the plant cell
rRNA
ribosomal RNA
These subunits join to form the ____________
ribosomal unit for protein synthesis.
Vesicles
sections of the membrane that pinch from the endoplasmic reticulum and form an envelope around the proteins and lipids
chloroplasts
are specialized organelles that give plants their green color and it is also where photosynthesis takes place.
Eukaryotic cells
cells that do have a nucleus and membrane-bound organelles, which help to organize and compartmentalize functions in the cell. They are larger and have more complex structures and DNA and make up both single and multicellular organisms such as plants, animals, and fungi
Prokaryotes
cells that lack a nucleus and membrane-bound organelles. They are smaller and simpler and include bacteria and archaea
Ribosomes
cellular organelles made up of multiple proteins and ribosomal RNA involved in the process of translation. They bind with the mRNA, allow the arrival of tRNA containing amino acids, and synthesize the peptide bond to form a polypeptide chain.
Thylakoids (Grana)
smaller oval-shaped structures, on the surface are photosynthetic chlorophyll
Microfilaments
smallest cytoskeletal component and also are readily remodeled. They are made of actin monomers twisted together in a long double helix. Microfilaments are important for cellular movement, cleavage furrow formation in cell division and muscular contraction.
import proteins
specialized group of protein that carries NLS-protein cargo into the nucleus
Chlorophyll is a pigment that is essential for photosynthesis, as it absorbs a specific wavelength of energy from
sunlight
outer membrane of mitochondria
surrounds the mitochondria. It is a semi-permeable membrane similar to the cell membrane.
isotonic environment
the central vacuole loses as much water as it receives, causing the plant cell to become soft and flaccid
hypertonic environment
the central vacuole will lose water, causing the plant cell to shrink in size
Ribosome Structure
contains many proteins that form the ribosomal complex can bee present in the cell in two forms: 1. free ribosome that is suspended in the cytosol. They can move freely, except in other organelles and the nucleus of the cell. 2. The second form is the membrane-bound ribosome that is attached to the endoplasmic reticulum. It is known as the rough endoplasmic reticulum.
Rough Endoplasmic Reticulum
contains ribosomes, the site of protein synthesis, the opening of the endoplasmic reticulum known as the lumen, responsible for modifying proteins by adding a carbohydrates
The proteins synthesized by free ribosomes remain in the
cytosol.
termination stage
the release factors bind with the termination codon and the synthesized polypeptide chain is released
eukaryotic cells
they have a unique membrane that surrounds them and a nucleus that regulates the functions of the cell
Why are only certain proteins allowed in the nucleus?
this is where essential DNA processes occur DNA instructions are carefully folded up and stored in the nucleus in the form of chromatin
Chlorophyll A, the type of chlorophyll used in photosynthesis, is located in the ________.
thylakoids
The nucleus and the nucleolus work together to function in the ____________ and ______________ processes.
transcription; translation
tRNA
transfer RNA
The endomembrane system is a system of membranes that
transport proteins and lipids out of the cell
Plant cells possess two structures that are essential to their overall function:
vacuoles and cell walls
Lysosomes
vesicles that contain enzymes that can digest other materials
Stacks of thylakoids are referred to as
granum
osmosis
- diffusion of water across a selectively permeable membrane. - Osmosis causes water to enter the central vacuole in order to balance the internal and external environments of the central vacuole.
Two Subunits of Ribosomes
- one larger subunit and one smaller subunit - rRNA and protein content in these subunits is different for eukaryotes and prokaryotes - smaller subunit has the binding site for messenger RNA, and the larger subunit has the E-site, P-site, and the A-site. These subunits join to form the ribosomal unit for protein synthesis.
Vacuoles
- responsible for allowing for the digestion of proteins and lipids, store water and wastes in the cell
The entire process of the lytic cycle is completed via the following five key steps:
1. Adsorption (Phage attachment) 2. Penetration (Bacterial cell entry) 3. Phage replication and biosynthesis of viral components 4. Maturation (Assembly of new virions) 5. Lysis of host cell and release of new virus particles.
Both prokaryotic and eukaryotic cells...
Contains DNA as the genetic material Contains cytoplasmUses ribosomes in protein synthesis Cell membrane made of phospholipids
Eukaryotes
Contains a nucleus and membrane bound organelles like mitochondria, endoplasmic reticulum, and chloroplastsPlants, animals and fungi10 - 100 micrometersUnicellular or multicellularDNA is linear and complex80S ribosomesCytoskeleton made of actin, intermediate filaments and microtubulesReproduces sexually or asexuallyDivides using mitosisOnly fungi and plants have a cell wall
Is DNA in the nucleus or the nucleolus?
DNA is found only in the nucleus of eukaryotic cells. The nucleolus is a smaller organelle, inside the nucleus, which primarily contains RNA.
chromatin
DNA packaged with the help of specialized proteins
The nucleolus structure can be broken down into several main components:
Fibrillar centers - Ribosomal proteins are formed here. Dense fibrillar component - Contains new rRNA that will bond with the ribosomal proteins. Granular component - Holds the rRNA as it bonds with ribosomal proteins to form completed ribosomes.
The Ribosome's Function: Three Stages
Initiation Elongation Termination
three main components to the cytoskeleton:
Microtubules Intermediate filaments Microfilaments
What is the basic structure of a mitochondria?
Mitochondria are spherical or rod-shaped organelles. Their diameter ranges from 0.5 -1 micrometer. They comprise two phospholipid bilayers (the inner and outer membrane), matrix, and invaginations of the inner membrane called cristae.
What is the structure and function of mitochondria?
Mitochondria structure comprises two phospholipid bilayers (the inner and outer membrane), matrix, and invaginations of the inner membrane called cristae. Mitochondria is the site of aerobic cellular respiration.
Prokaryotes
No nucleus or membrane bound organellesBacteria and archaea only0.1 micrometer to 5 micrometersUnicellular onlyDNA is circular70S ribosomesCytoskeleton made of analogous proteinsReproduces asexually onlyDivides using binary fissionAll have a cell wall
process of the lytic cycle
Phages with the lytic cycle are called temperate or non-virulent phages. Lytic cycle results in the killing of the host bacterium by cell lysis. Lytic cycle does not have a prophage stage. Phage genome replication occurs independently of the host DNA replication. Phage genome completely takes over the cellular mechanism of the host. Phage genome productivity is high in the lytic cycle. Lytic cycle occurs quickly and progeny virus particles are produced. Lytic cycle does not follow the lysogenic cycle.
What do prokaryotic and eukaryotic cells have in common?
Prokaryotic and eukaryotic cells also have some properties in common, including being alive, having a cell membrane, having DNA, ribosomes, and the ability to divide and reproduce.
What are stroma and grana?
Stroma is the aqueous fluid filling the chloroplast cavity, where the light-independent reaction process of photosynthesis takes place. Granum is stacks of thylakoids, which are also called grana. It is where chlorophyll is stored.
What's the stroma in a chloroplast?
Stroma is the liquidus material found throughout the cavity of the chloroplast. It is where the light-independent reaction process of photosynthesis takes place.
T or F: The endomembrane function is important because being able to produce proteins is pointless if the proteins can't be transported out of the cell. The endomembrane system is a method for transporting proteins out of the cell.
T
cellular respiration
a process that converts food into usable chemical energy in your cells
translation
a process that creates proteins from mRNA
The lysogenic cycle follows the process of
adsorption, penetration, phage genome integration into bacterial chromosome (prophage) followed by phage genome replication along with the replication of the host genome. The presence of a prophage elicits changes in certain phenotypes of the host, the process known as lysogenic conversion.
Plant cells are
eukaryotic cells
The empty phage particle which remains outside the host bacteria is called the
ghost.
The proteins synthesized by membrane-bound ribosomes are transferred to
the endoplasmic reticulum and further to the Golgi apparatus for processing.
Initiation Stage
the first amino acid-bearing tRNA arrives at the P-site
DNA
the genetic material present inside the nucleus of the cell. It has the information coding for all the proteins that are synthesized in the body
Microtubules
the largest cytoskeletal component and are constantly being remodeled. They are made of tubulin arranged in a hollow tube and help with intracellular transport, cell division, cell polarity and are arranged in a 9 + 2 orientation in cilia and flagella.
Stroma
the liquid material found throughout the cavity of the chloroplast. The function of the stroma is to provide volume around the different structures inside of the chloroplast for protection. Chloroplast DNA is different from most other cells as it contains both DNA and Ribosomes.
elongation stage
the peptide bond is formed between the incoming tRNA and the ribosome translocate on the mRNA
transcription
the process of creating different types of RNA from DNA. Transcription would be like making copies of individual pages of the owner's manual that can then be passed out and read by the rest of the cell. a segment of the double stranded DNA molecule is unwound and separated with the help of enzymes. A complementary strand of mRNA is then constructed containing protein-making instructions which can be carried out of the nucleus. Once the mRNA reaches a ribosome, rRNA reads and translates the genetic information to create long chains of amino acids called proteins mRNA, rRNA, and tRNA - are created by the process of transcription within the nucleus.