Special Sub-Topic: Animal Cell Structure
|Let's start first with a basic outline of the structure of an animal cell. You know that the shape, size and functions of all eukaryotic cells (there are 2 types of cells, prokaryotic and eukaryotic, out of which in this quiz you needn't bother about prokaryotic cells) varies, yet they all have three main functional regions, namely the plasma membrane, nucleus and cytoplasm.
What is the name given to the nucleus and cytoplasm of a cell combined?|
protoplasm. Protoplasm is an aggregate of molecules of various chemicals, most of these being organic molecules like proteins, fats, carbohydrates, etc. In layman's terms, it is basically everything that lies within the plasma membrane, which is the outer boundary of the cell.
Cytoplasm includes everything in the cell leaving out the nucleus and plasma membrane; which is basically all the cell-organelles and their medium.
|The plasma membrane is the outer covering of every cell, which separates its contents from everything around it. It provides a mechanical barrier for the protection of the inner cell contents. It is said to be "selectively permeable". What does this mean? |
The plasma membrane regulates the movement of molecules in and out of the cell.. The plasma membrane is made up of lipids and proteins, and it provides a mechanical barrier for protection of the inner cell contents. It is both supple and strong. By being selectively permeable, it allows necessary molecules to move in and out of the cell, whilst blocking harmful substances from entering the cell.
|The nucleus is a prominent spherical or oval structure, located usually near the centre of the cell. It is the "control centre" of all cell activities. Which of the following do *NOT* form a part of the nucleus of a eukaryotic animal cell?|
mitochondria. The chief components of the nucleus of a eukaryotic animal cell are:
- The nuclear membrane, which is a double-layered membrane which separates the nucleus from the cytoplasm. The presence of a nuclear membrane around the nucleus is the main distinguishing factor between prokaryotes (which include bacteria and other simple organisms) and eukaryotes (which are far more complex creatures, such as US).
- The nucleolus, which contains RNA (ribonucleic acid) which helps synthesize proteins.
- Chromatin material, which contains DNA (deoxyribonucleic acid), and is responsible for storing and transmitting hereditary information from one generation to the next.
- Nucleoplasm, which is similar to cytoplasm, is and is basically the matrix or medium of the nucleus.
|Endoplasmic reticulum (ER) is a membranous network present in cells, which encloses a fluid-filled lumen. It is of two types: rough endoplasmic reticulum, which has ribosomes (another type of cell organelle) attached to it, and smooth endoplasmic reticulum, which doesn't have ribosomes.
Now state if the following statement is 'true' or if it is 'false': Rough ER is involved in synthesizing proteins whereas smooth ER synthesizes lipids.|
t. Rough endoplasmic reticulum which has ribosomes on its surface secrete proteins whereas smooth endoplasmic reticulum secretes lipids. Some of the proteins and lipids synthesized in ER are used for producing new cell parts, especially the cell membrane. Some others function as hormones or enzymes.
Ribosomes are also present separately in the cytoplasm.
|This cell organelle packages material synthesized in the ER and dispatches it to targets both intracellular and extracellular. It is also involved in the formation of lysosomes and peroxisomes. It was discovered by an Italian anatomist in the late 19th century.
This cell organelle is called _____ apparatus/complex/body.|
Golgi. Golgi apparatus was discovered by Camillo Golgi, from where it gets its name. It consists of a set of smooth, flattened sac-like structures called 'cisternae'. These are usually stacked together in parallel rows.
|These are small membrane-bound sacs containing powerful oxidative enzymes. They are specialized for carrying out oxidative reactions, which include the removal of toxic substances. They are mostly found in kidney and liver cells. Which cell organelles are these?|
peroxisomes. Peroxisomes also convert cellular material to hydrogen peroxide (H2O2) or glucose.
|Mitochondria are rod-shaped organelles, bordered by a double membrane. The outer membrane is smooth and the inner one is folded. What are these finger-like folds called?|
cristae. Cristae greatly increase the surface area of the inner membrane of the mitochondrion.
|These cell organelles contain enzymes for cellular respiration in which energy is released. Energy from consumed food molecules is converted into usable energy, stored as ATP (adenosine tri phosphate) molecules. These organelles are hence called 'power plants' of the cell. Which cell organelles am I talking about?|
mitochondria. In mitochondria, the cristae are the location of ATP synthesis and their folds greatly increase the surface area for this.
In case you're not sure about what exactly cellular respiration is, I'll give a brief overview: Respiration is of two parts- breathing and cellular respiration. When you breathe you take in oxygen, which the blood transports to all the cells in the body. Now comes cellular respiration. Using the oxygen you obtained from breathing, glucose (which you obtain from carbohydrate-rich food) gets oxidised to form ATP molecules, which is a form of energy the body can use. *The cellular respiration occurs in mitochondria.* Hence, both oxygen and carbohydrates directly help give us energy.
|This cell organelle consists of two granule-like centrioles and is found in animal cells only. It helps in cell division. What is it called?|
centrosome. A centrosome (not to be confused with "centromere", which is the point of intersection of the two chromatids during cell-division) is made up of two centrioles, which separate at the time of cell division. They let out "spindle fibres", which separate replicated chromosomes for the two daughter cells.
|These are membrane-bound vesicles and are present in plenty in every cell. They contain powerful enzymes capable of either digesting or breaking down all organic material. They are called "digestive bags", because they serve as an intracellular digestive system, i.e. a mini-digestive system within the cell. They destroy any foreign material that manages to make it it inside the cell, such as bacteria, etc. They also remove worn-out or poorly functioning organelles from the cell. They may even sometimes digest the entire damaged or dead cells containing them, hence the second nick-name - "suicide bags".
What are these cell organelles?|
lysosomes. Hope playing this quiz was a fun and educational experience! :-)
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