Cellular Differences - Biology

Plant cells are very similar to animal cells, but receive energy from sunlight. As a result, they require chloroplasts in order to house the chlorophyll where photosynthesis takes place. Animal cells are incapable of photosynthesis, and do not contain chloroplasts.

The other listed structures are found in both animal and plant cells.

Both plant and animal cells contain a nucleus, endoplasmic reticulum, and cell membrane. Plants and animals are both eukaryotic, meaning they have the ability to house membrane-bound organelles.

Chloroplasts are required for producing chlorophyll from sunlight. Animals are incapable of performing photosynthesis because they lack these structures; only plant cells and certain protists contain chloroplasts. Additionally, all plant cells contain vacuoles, while only a subset of animal cells do.

Mitochondria are membrane-bound organelles found in both plant and animal cells, and provide energy for the cell by converting different forms of reactants into ATP. The cell membrane is present in both types of cells and separates the environment from the inside of the cell, and provides cell structure and protection. The rough endoplasmic reticulum is present in both types of cells and is responsible for the storage and packaging of proteins and vesicles. The nucleus is present in both types of cells and controls the general activities of the cell, including gene expression and cell division.

Of these answer choices, only chloroplasts are present in plants cells, but not animal cells. Plant cells are photosynthetic and create their own form of energy from sunlight. The photosynthesis occurs in the chloroplasts of plant cells, which contain the pigment chlorophyll.

Chlorophyll is a pigment found in chloroplasts of plant cells. The electrons of chlorophyll become excited by certain wavelengths of light, and can use this energy to create chemical bonds. This process is known as photosynthesis. The net result of photosynthesis is the conversion of electromagnetic waves (light) to chemical energy (sugar).

Wavelengths that correspond to green light are not used by chlorophyll, and are not absorbed by the pigment. Green light is reflected back from the leaves of the plant, and absorbed by the eyes of an observer. This is what makes leaves look green.

Plant cells contain chloroplasts and are surrounded by a cell wall. Pectin is a carbohydrate found in the cell wall outside of the cell. The middle lamella is a structure composed of pectin and is used to hold adjacent cell walls together, similar to the action of a desmosome.

Chloroplasts are the only option that is located within the cytosol of the plant cell.

Both plant cells and fungal cells have cell walls; animal cells do not. Plant cells have chloroplasts, but neither fungal cells nor animal cells do. Fungal, plant and animal cells all have plasma membranes and mitochondria.

All of the options are true for animal cells except for the existence of plasmodesmata, which are found in plant cells. Plasmodesmata are small gaps in the cell walls. They are like gap junctions in animal cells, allowing for communication between cells and the exchange of minerals throughout the plant.

Hypertonicity and hypotonicity are both relative terms. A hypertonic solution has more dissolved solutes than the cell that is submerged within it. In other words the solution has less water than the cell in the solution. A hypotonic solution is one that has less dissolved solutes (i.e. more water) than the cell or membrane within it. Water follows its concentration gradient: it flows to where it is least concentrated.

A plant's vacuole is a large membrane bound compartment within the cell that plays a structural role when it has the proper turgor pressure. It is also used as storage for various molecules. Salad generally becomes wilted in salad dressing—or other liquids with many dissolved solutes—because the water in the plant cells tends to flow outward or down its concentration gradient. Hence the salad leaves wilt because they are in a hypertonic solution. In other words, there are more dissolved solutes and non-water molecules outside the cells than there are inside. In terms of water, there is less water outside the cell than in it and so the water flows down its concentration gradient and out of the cell to equalize the gradient. This causes the vacuole to shrink, which reduces pressure on the cell wall and gives the wilted appearance.

Prokaryotic cells are defined as cells that lack membrane-bound organelles, such as the nucleus. Prokaryotic cells still have DNA as their genetic material, however it is located in the cytoplasm in a circular structure known as the nucleoid. The nucleoid is unique to prokaryotes because it lacks a nuclear envelope.

Prokaryotic cells have cytoplasm contained inside of a plasma membrane, and often a cell wall. They also have ribosomes in the cytoplasm to carry out protein synthesis.

Eukaryotes are much more complex and have numerous organelles, including the endoplasmic reticulum, Gogli apparatus, lysosomes, and mitochondria.

Much like eukaryotes, prokaryotes are capable of translating their own proteins. Prokaryotes follow the same central dogma as eukaryotic cells, using DNA to transcribe mRNA and using mRNA and ribosomes to build proteins from amino acids. Ribosomes are primarily composed of rRNA, and are not bound by a membrane.

Prokaryotes lack a nucleus, as well as complex membrane-bound organelles such as mitochondria and chloroplasts.

The primary difference between prokaryotes and eukaryotes is the presence of membrane-bound organelles. Prokaryotes lack any membrane-bound organelles, including a nucleus, while eukaryotes possess these structures. All cell types have an outer cell membrane, which contains the cytosol, DNA, and ribosomes. Ribosomes are not bound by membranes, and are essential for translating proteins. Both prokaryotes and eukaryotes use transcription to convert DNA to RNA and translation to convert RNA to proteins.

Mitochondria are only found in eukaryotes and are used to produce ATP via oxidative phosphorylation. A circular chromosome is characteristic of prokaryotes, since they lack a nucleus. Both prokaryotes and eukaryotes can have cell walls.

Prokaryotes are much smaller in size than eukaryotes. Eukaryotes are known for their membrane-bound organelles, such as the mitochondria, vesicles, and vacuoles. Prokaryotes do not have membrane-bound organelles. Some eukaryotic organisms go through the process of meiosis in order to produce variation for sexual reproduction.

Prokaryotes undergo a different process to reproduce asexually, called binary fission. The DNA of prokaryotes are contained in a circular chromosome called a nucleoid, which is replicated completely. The cell then splits in two, with each having an exact copy of the same plasmid. Prokaryotes lack a nucleus by definition.

The prokaryotic ribosome is smaller, at 70S, while the eukaryotic ribosome is larger, at 80S. The ribosomes also contain different sized subunits. Prokaryotic ribosomes are made of a 30S and 50S subunit to form the full 70S structure. Eukaryotic ribosomes are made of a 40S and 60S subunit to form the full 80S ribosome.

Eukaryotes and prokaryotes split during evolution when eukaryotic cells adapted membrane-bound organelles. These organelles include the endoplasmic reticulum, mitochondria, chloroplasts, Golgi apparatus, and nucleus (among others). Prokaryotes lack all of these structures.

All cells, however, contain DNA and ribosomes in order to synthesize proteins and maintain metabolic processes. Ribosomes are not bound by membranes, and are instead made of ribosomal RNA (rRNA) and proteins. Both prokaryotes and eukaryotes can have cell walls, though the structure and composition of the cell wall can vary.

It is important to remember that there are multiple types of eukaryotes. All eukaryotes have a plasma membrane, ribosomes, and cytosol since these are fundamental organelles necessary for basic cellular function. Plant and fungi cells, which are eukaryotic, also possess cell walls. Thus, the answer is "none of the other answer choices."

Eukaryotes and prokaryotes are distinguished based on a structure called the nucleus. Eukaryotes have a nucleus, which houses their genetic material. Prokaryotes do not have a nucleus; instead their DNA is localized in an area (i.e. it is not membrane bound). So if the researcher were to stain a sample containing both types of cells, the eukaryotic cells would have darker, more defined stains within their cells. This would indicate the presence of a more compacted and localized DNA than that found in prokaryotes.

Bacteria are prokaryotes, not eukaryotes. Eukaryotes have membrane-bound organelles and an enclosed nucleus. “Mitochondria” is incorrect and it refers to an organelle in eukaryotes. Muscle cells in humans and plant cells are also eukaryotic cells.

Like other eukaryotes, fungal cells contain a membrane bound nucleus with chromosomes. They also possess membrane bound cytoplasmic organelles such as ribosomes and mitochondria. A prokaryote is a single celled organism that lacks a membrane bound nucleus, mitochondria, or any other membrane bound organelles.

Obligate organisms require a certain environment in order to survive. Facultative organisms have a preference but can usually survive multiple environments. Therefore, a bacteria that requires an oxygen-free environment is an obligate anaerobe. Obligate anaerobes are microorganisms that are killed by normal atmospheric concentrations of oxygen.

Both eukaryotic and prokaryotic cells have cell membranes. However, the prokaryotic cell membrane is surrounded by a cell wall. Prokaryotes have circular DNA, whereas eukaryotic DNA is in chromosomes and bound by histone proteins. Prokaryotes do not have membrane-bound organelles (endoplasmic reticulum, mitochondria, chloroplasts, Golgi bodies, nucleus). Prokaryotic ribosomes are smaller (70s) than eukaryotic ribosomes (80s).

The cytoskeletion determines cell shape. The cytoskeleton consists of three different types of filamentous proteins: microfilaments, intermediate filaments, and microtubules. Elements of the cytoskeleton can interact with the cell membrane and cell junctions to alter the cell's overall structure.

There are no cell walls in animal cells, although the cell wall does play a large part in determining cell shape in organisms that possess them (plants, bacteria, fungi).