Generate Quiz 6AA5675B1D2A6

Bacterial cells do not divide mitotically or meiotically; instead, they divide via binary fission. Spindle formation, which is facilitated by microtubules, guarantees meiosis and mitosis in eukaryotic cells.

Prokaryotic and eukaryotic cell membranes contain globular proteins, polysaccharides, and phospholipids, but only eukaryotic cell membranes contain cholesterol.

Centrifugation is a technique that involves rapidly spinning molecules with varying densities around an axis in solution. Option A is thus the right one.

The structure known as the phragmoplast is responsible for creating a cell wall, or “cell plate,” between daughter cells. It is a defining trait of certain, but not all, eukaryotic cells. Thus, in this case, option D is the best one.

Vacuoles contain a single layer of tonoplast as its membrane, whereas the nucleus, mitochondria, and chloroplasts all have two layers.

In eukaryotes, mitochondria are the double-membrane-bounded organelles.It is the cell’s power source.

Organization:

Numerous cristae, or folds, are formed by the inner membrane and extend into the organelle’s interior (or matrix). Each of these elements has a specific purpose, and the inner membrane and matrix serve as the main mitochondrial working compartments. The outer membrane of the mitochondria is a double phospholipid membrane that encloses the inner matrix, inner membrane, and intermembrane gap.

Functions:

The structure of the outer membrane is comparable to that of the plasma membrane. It facilitates the bond between the cytoplasm and the inner mitochondria. The production of ATP takes place in the inner membrane.

Thus, the outer and inner membranes of mitochondria differ in both structure and function.

Ribosomes are present in both prokaryotic and eukaryotic cells, but only eukaryotic cells contain linear chromosomes, a membrane-bound nucleus, and a cellulose cell wall.

In vertebrates’ livers, the SER detoxifies toxins and medications.

It was Singer and Nicolson, not Virchow, who developed the Fluid Mosaic idea in the early 1970s. Every other one is matched appropriately.

The multi-step process of cell fractionation usually consists of centrifugation to separate the cell components according to their density after homogenization. Other techniques, including gel electrophoresis or ultracentrifugation, can subsequently be used to further purify the various cell components.

Muscle cells have a specific kind of endoplasmic reticulum called the sarcoplasmic reticulum. It is in charge of holding and releasing the calcium ions required for contraction of muscles. Although the sarcoplasmic reticulum lacks ribosomes, it shares structural similarities with the endoplasmic reticulum (hence the response A). The effective release of calcium ions during muscle contraction is made possible by the highly specialized and repetitive pattern of the sarcoplasmic reticulum.

It is incorrect to say that glyoxysomes can supply energy. They include flavine oxidases, which catalyze the substrate-dependent reduction of oxygen to H2O2, rather than mitochondria’s energy-coupled electron transport mechanism.

The ‘Golgi apparatus’ is a cellular organelle that is in charge of altering and transporting proteins to other organelles, including the cell’s digestive organelle, the lysosome.

The cell membrane’s job is to create the cell’s perimeter. The cell membrane encloses the protoplasm.

Nine triplets of microtubules arranged in radial symmetry make up a typical centriole.

The cytoskeleton of a cell contains microfilaments, also known as actin filaments, which are polymers of the protein actin.

Microvilli are tiny protrusions from the cellular membrane that serve a number of purposes by increasing the surface area available for diffusion and reducing any volume growth.

The cytoskeletal system of the cell depends on intermediate filaments. They could participate in specific junctions or stabilize organelles like the nucleus. They are 8–10 nm in size, and they differ from “thin filaments” in that the latter are movable.

In 1665, British scientist Robert Hooke coined the term “cell” to describe these minuscule units of life. He was shocked to observe what seemed to be a honeycomb when he examined a small piece of cork under his microscope. He discovered that the cork was composed of several little units, or what Hooke referred to as cells.

Nine microtubule triplets (9×3 = 27) make up each centriole.

As the name implies, Camillo Golgi made the discovery of the Golgi complex.

The process of exocytosis involves the fusing of the cell membrane with the vacuole membrane, releasing the contents of the vacuole to the outside. The membrane’s surface area is increased by this fusion. A part of the cell membrane is consumed in the process of phagocytosis or endocytosis in order to create the vesicle.

9×3=27 because centrioles are normally composed of nine pairs of short microtubule triplets organized in a cylinder.

In opposition to the idea of abiogenesis, Rudolph Virchow stated that new cells are created by the division of pre-existing cells, in accordance with the cell theory.

A telocentric chromosome is one in which a centromere remains at one end. While telocentric chromosomes are uncommon in humans, they are more prevalent in other animals like insects and plants. When a chromosome splits at its centromere, telocentric chromosomes are created.

The primary source of the turgor that supports each individual plant cell and makes the leaves and other immature plant parts stiff is the plant vacuole.

Svedberg units are represented by the letter S in the ribosomal subunits. It symbolizes the various ribosome sedimentation rates that occur during centrifugation.

In eukaryotes, the 60s and 40s ribosomal subunits combine to produce an 80S ribosome.

Two points that are one millimeter apart may be distinguished by the human eye. The human eye cannot distinguish between them at distances less than 1 mm, hence a microscope is required.

80S ribosomes are made up of the 60S and 40S subunits.

In Tay-Sachs illness, a buildup of lipids in the cell impairs brain function and a lipid-digesting enzyme is absent or inactive.

The fundamental structural foundation of all cell membrane types is provided by lipoproteins, which are made up of lipids and proteins.

A sialoglycoprotein found in red blood cell membranes is called glycophorin. Although it has no direct connection to any of the illnesses, some of its variants are resistant to malaria, an illness spread by mosquitoes.

Vacuoles lack the genetic material and protein-synthesising capabilities of mitochondria and chloroplasts, which allow them to replicate themselves.

The cell wall, slime, and capsule are all part of the cell envelope. The bacterial envelope comprises a double-layered cell membrane and a peptidoglycan-based cell wall. Slime is a component of the capsule, which is found outside the cell membrane.

‘Compound microscope’ is the tool used to magnify the picture of an item that is invisible to the human eye. The ‘objective lens’ enlarges the image of the item, while the ‘ocular lens’ enlarges the picture created by the first lens. The sum of the magnifications of the two lens systems is the overall magnification. This means that the item would be magnified by 10 × 10 = ‘100 times’ by the microscope, which has a 10X objective lens and a 10X ocular lens.

Adult stem cells derived from various sources that have the ability to develop into multiple cell types are known as “mesenchymal” stem cells. These sources in humans include amniotic fluid, bone marrow, adipose tissue, and umbilical cord tissue. Most of the time, they are not cellular.

The magnification of an electron microscope ranges from 100,000x to 300,000x.

RER, microtubules, and ribosomes are found in both plant and animal cells, whereas centrioles are only found in animal cells.

Given that Antonie van Leeuwenhoek was the first to see bacteria and protozoa using a compound microscope, Option A is accurate.

The reproductive cells known as gametes, which include the egg and sperm cells, are haploid, which means they only have one pair of chromosomes. Humans have twenty-three haploid chromosomes.
The parent cell divides twice to create four daughter cells, each of which has half as many chromosomes as the parent cell, during meiosis, the process of cell division that results in gametes. This guarantees that the developing zygote will have the typical diploid number of chromosomes—46 in humans—when the egg and sperm combine during fertilization.

The nucleolus, a unique part of the cell nucleus that resembles a dense region and houses the genes encoding rRNA, is where rRNA molecules are generated.

This is accurate. The golgi complex, ribosomes, and the approximate endoplasmic reticulum are all involved in protein synthesis in one way or another. Initial protein synthesis takes place in the rough endoplasmic reticulum, proteins are processed and altered by the golgi complex, and the crucial machinery where protein synthesis takes place is the ribosome.

Prokaryotic cells, sieve tube cells, and red blood cells do not have nuclei.

Cells made of cellulose are stronger and more stiff. It forms the cell wall of plants.
The polysaccharides cellulose, hemicelluloses, and pectin make up the primary wall (a).
b) Secondary wall: Cellulose, xylan, glucomannan, and lignin are the primary constituents of secondary walls. But compared to the primary cell wall, the secondary cell wall has more cellulose.

c) Middle Lamella: Pectins make up the majority of this layer.

Option C is accurate. Here, exocytosis is also known as secretion (material leaving the cell), while all other possibilities indicate that chemicals are being ingested.

Cells known as phagocytes may absorb and occasionally break down foreign substances like bacteria, carbon, dust, or dye. They surround the foreign particle and create a vacuole when they consume it by expanding their cytoplasm into pseudopods, which are cytoplasmic projections that resemble feet. Living cells may absorb liquid droplets through a process called pinocytosis. Thus, pinocytosis is known as cell drinking and phagocytosis as cell devouring.

One kind of endoplasmic reticulum that lacks ribosomes embedded in its membrane is the smooth endoplasmic reticulum. Numerous toxins and medications, including lipid-soluble medications, aspirin, DDT-containing pesticides, petroleum products, and pollutants, are detoxified by it and changed into safer water-soluble alternatives.

According to the hypothesis, the membrane is a bilayer of phospholipids in which protein molecules are either fully or partly buried. Like big icebergs floating in the ocean, the proteins are dispersed in an asymmetrical fashion throughout the membrane. Protein distribution patterns might differ between membranes as well as between the membrane’s two surfaces. The thickness of the membrane is around 7 nm.

The chromoplasts are plastids, which are heterogeneous organelles that store and synthesize carotenoid colors in fruits and flowers.

In the context of bacteria, protoplasm refers to the whole contents of a bacterial cell, excluding exterior features like as the capsule, slime, cell wall, and cell membrane. It consists of the following main parts: Organelles, ribosomes, nucleoids, cytoplasm, and inclusion bodies.

The nucleus has ribosome subunits that are generated in the darkly pigmented region known as the nucleolus, whereas mitochondria and chloroplasts have 70 ribosomes. However, the golgi apparatus lacks ribosomes.

The chloroplast’s stroma is the fluid-filled area.

RER is responsible for protein synthesis, whereas SER is responsible for drug detoxification. Yet, both SER and RER are responsible for mechanical support.

The cytoplasm serves as a storehouse for the molecules needed for cellular functions.

The two primary locations for the synthesis of cell wall components are the Golgi and plasma membranes.

The two layers of phospholipids were arranged in a fluid mosaic model of the plasma membrane, with hydrophilic interactions occurring at random with embedded proteins at the intracellular and external faces and hydrophobic interactions stabilizing the two layers internally.

All of the job is completed at the Golgi complex, after which it is transferred to other organelles or cells, for example. The Golgi complex is where material packing takes place, and the endoplasmic reticulum is one kind of factory.

Glycoproteins in cell plasma membranes have receptors called integrins. They are transmembrane proteins with many subunits. Their extracellular domains are vast and made up of separately organized subdomains that are covalently joined by flexible linkers.

A lipid bilayer connected to proteins makes up the plasma membrane. The non-polar phospholipid tails are hydrophobic and oriented inward, facing one another, whereas the polar phospholipid heads are hydrophilic and oriented outward. As a result, the hydrophilic ends come into touch with the cell’s internal environment as well as the exterior extracellular environment.

The ribosome is where proteins are made. However, the nucleolus is the factory that produces ribosomes.

The inner mitochondrial membrane of eukaryotes contains the electron transport chain. It is found inside the plasma membrane of prokaryotes.

Since ‘phosphatidylserine residues’ are only present on the inner side of the cellular membrane in healthy cells, option B is accurate. ‘Apoptosis’ involves the movement of phosphatidylserine to the cell’s outer surface.

Fatty acid catabolism is carried on by mitochondria, whilst lipid synthesis occurs in SER.

A polysome is a collection of ribosomes that are joined to mRNA.

In nature, all enzymes are proteins. After being produced on the RER, lysosomal enzymes are carried by the SER to the Golgi complex, where they develop into primary lysosomes.

The plasma membrane is referred to as a lipid-bilayer because it is composed of two phospholipid layers. The heads of both phospholipids face the cytoplasm and extracellular space, while the non-polar tails face one another.

The envelope, stroma, and thylakoid are the three components that make up chloroplasts. Light-dependent photosynthesis processes occur in the thylakoid.

Chloroplasts are clearly visible under a light microscope because of their size in relation to the endoplasmic reticulum, Golgi apparatus, and ribosomes.

The organelles mitochondria and chloroplasts, which are found in eukaryotic cells, also include ribosomes 70S. Prokaryotic cells only contain 70S ribosomes in their cytoplasm, whereas eukaryotic cells (algae, fungus, and protozoa) have 80S ribosomes. Option D is therefore accurate.

Together with 70S ribosomes, which are likewise comparable to those in prokaryotes, like bacteria, chloroplasts and mitochondria are the two organelles that have circular DNA that resembles that of prokaryotic cells. The endosymbiotic hypothesis, which holds that mitochondria and chloroplasts are ancient prokaryotes, is where this all began.

Because the lipid bilayer cell membrane of a cell is selectively permeable—that is, only a small number of molecules, mostly nonpolar ones, may flow through it—it is always semi-permeable.

Transport vesicles, which transport proteins, lipids, and other molecules to their designated locations inside the cell or for secretion outside the cell, are among the many vesicles that are formed by the Golgi apparatus. Vesicle generation would be significantly hampered in the absence of the Golgi apparatus.

Prokaryotes lack the nucleus and membrane-bound organelles found in eukaryotic cells.One characteristic that does not differentiate prokaryotes from eukaryotes is the cell wall.

The endoplasmic reticulum (ER) is a network of interconnected cisternae (long, closed sacs) that are typically found throughout the cytoplasm of all eukaryotic cells, extending from the nuclear membrane to the plasma membrane.

Thin filaments made of the protein actin are called microfilaments or actin filaments. They are a component of the cytoskeleton and are involved in muscle contraction, cell movement, and changes in cell shape. Cyclosis or amoeboid motions are directly caused by microfilaments.

Chromosomes that are found in the nucleus contain nucleotides. Since genetic information is present in all of these possibilities, they are all true.

Multiplying the eyepiece’s (ocular lens’s) magnification by the objective lens’s magnification yields the overall magnification of an item seen under a microscope. In this instance, a 10X objective lens and a 5X eyepiece are being used.

Eyepiece magnification x objective magnification equals total magnification.

5X x 10X is the total magnification.

50X is the total magnification.

Therefore, using the specified microscope configuration, the item will be magnified fifty times. The enlarged picture size of an item with an actual size of 15 mm is:

Actual size × total magnification equals the magnified picture size.

Image size magnified: 15 mm × 50X

750 mm is the magnified picture size.

The image will be 750 mm in size when enlarged.

The most basic thing that can function as a separate unit of life is the cell. A single cell or a collection of few to many cells makes up every known living thing.

It is accurate to say that “plant cells have 80S ribosomes while bacterial cells have 70S ribosomes.” The 70S ribosomes that are often found in bacterial cells are smaller and less complicated than the 80S ribosomes that are present in eukaryotic cells, such as plant cells.

It’s also accurate to say that “plant cells divide by mitosis, while bacteria divide by binary fission.” Binary fission is the method by which bacterial cells divide into two identical daughter cells. However, the more complicated process of mitosis, which involves the division and distribution of genetic material into two daughter cells, is how plant cells and other eukaryotic cells divide.

The claim that “plant cells have a nuclear membrane while bacterial cells do not” is also accurate. The cells of bacteria are prokaryotic.

O2 is released as a result of photosynthesis, which involves chloroplasts.

Cells’ Smooth Endoplasmic Reticulum (SER) is where lipid metabolism mostly takes place.

A variety of lipids, including phospholipids, which are crucial parts of cell membranes, are synthesized by the SER. Additionally, it produces the lipoproteins that carry lipids throughout the body. Furthermore, through a mechanism known as lipolysis, the SER contributes to the breakdown (catabolism) of certain lipids, including triglycerides.

Lipid metabolism does not directly involve the nucleus (option A). The genetic material (DNA) of the cell is found in the nucleus, which is also principally in charge of regulating and expressing genes.

Proteins and lipids produced in the ER are modified, sorted, and packaged by the Golgi complex (option B). Although it indirectly contributes to lipid metabolism,

The most prevalent protein in microtubules is tubulin, whereas microfilaments contain myosin, actin, and tropomyosin.

The tonoplast is a vacuole membrane. The flow of water molecules between the cytoplasm, plasma membrane, and plasmodesmata is known as the symplast route. The outermost layer of an embryo is called an epiblast. Protoplast, Option B, is thus the response.

Since the middle lamella is the layer of material that sits between neighboring plant cells, Option C is accurate. It includes pectins, which are also employed as gelling agents in food, and it cements the cells together.

Eukaryotic ribosomes are ribonucleoprotein particles because they are made up of about equal quantities of protein and RNA (ribonucleic acid).

A big central vacuole that forms by connecting smaller vacuoles is often present in mature plant cells.

The amount of phospholipid that is present in the cell membrane determines how permeable it is. The cell membrane does not include any of the other chemical substances listed, such as cellulose, polysaccharides, and carbohydrates.

It is clear from the diagram that lowering the difference in glucose concentration between the surrounding liquid and within the visking tubing will occur as the concentration of glucose in the surrounding tube increases. Statement I is untrue as there would be less net diffusion of water due to a smaller concentration gradient. Statement II is accurate as there would be less variation in the glucose concentration, which would shorten the time needed to attain equilibrium. Statement III is accurate since a smaller concentration gradient would need less net water movement to reach equilibrium, which would result in a smaller volume change. Statement IV is untrue since there is no movement of the glucose molecules.