Cellular Differences - Biology

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.

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).

The unstable form of energy that is syntheisized refers to ATP. ATP is an unstable; its three phosphate groups are all negatively charged and repel one another. Remember that BOTH the mitochondria and chloroplast participate in ATP synthesis via chemiosmosis; however, only the chloroplast participates in glucose synthesis via photosynthesis. Note that glucose is a stable form of energy and is not readily usable until it is broken down in the process known as glycolysis.

The nucleolus is a subdivision of the nucleus; thus, it is only found in eukaryotes. It is the site of ribosome assembly. The nucleolus is made of RNA and proteins.

Histones are proteins found in the nucleus of eukaryotic cells. DNA wraps itself around histones to further condense. Also, depending on how tightly the DNA is wrapped around the histones, it may or may not be availible for activity (e.g. replication or transcription). Cells modify the interaction between DNA and histones around certain genes under certain conditions to make those genes available or unavailable as needed.

Vacuoles are membrane-bound structures that are found in bacterial, plant, fungal, and occasionally, animal cells. Vacuoles function in storage of water and waste and in maintenance of turgor pressure in plants.

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).

The unstable form of energy that is syntheisized refers to ATP. ATP is an unstable; its three phosphate groups are all negatively charged and repel one another. Remember that BOTH the mitochondria and chloroplast participate in ATP synthesis via chemiosmosis; however, only the chloroplast participates in glucose synthesis via photosynthesis. Note that glucose is a stable form of energy and is not readily usable until it is broken down in the process known as glycolysis.

The nucleolus is a subdivision of the nucleus; thus, it is only found in eukaryotes. It is the site of ribosome assembly. The nucleolus is made of RNA and proteins.

Histones are proteins found in the nucleus of eukaryotic cells. DNA wraps itself around histones to further condense. Also, depending on how tightly the DNA is wrapped around the histones, it may or may not be availible for activity (e.g. replication or transcription). Cells modify the interaction between DNA and histones around certain genes under certain conditions to make those genes available or unavailable as needed.

Vacuoles are membrane-bound structures that are found in bacterial, plant, fungal, and occasionally, animal cells. Vacuoles function in storage of water and waste and in maintenance of turgor pressure in plants.

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.