Cells Test

A granum is a coin-shaped stack of thylakoids which are the membrane-like structures found inside the chloroplasts of plant cells.

Chloroplasts work to convert the light energy of the Sun into the sugars that can be used by cells.

Nexin is a proteinous inter-doublet linkage that prevents microtubules in the outer layer of axonemes from movement with respect to each other.

The centrosome is an organelle that serves as a microtubule organizing center during cell division.

Semi-autonomous organelles are organelles with DNA. In eukaryotic cells, mitochondrion and chloroplast are semi-autonomous organelles.

Receptor-mediated endocytosis (RME), also called clathrin-mediated endocytosis, is a process by which cells absorb metabolites, hormones, other proteins and in some cases viruses by the inward budding of plasma membrane vesicles, containing proteins with receptor sites specific to the molecules.

Electron microscope is a microscope with high magnification and resolution, employing electron beams in the place of light and using electron lenses. It is used to visualise plasma membrane.

Microtubules are a component of the cytoskeleton found throughout the cytoplasm. In eukaryotes, microtubules are long and hollow cylinders made up of polymerised α- and β-tubulin dimers.

A contractile vacuole (CV) is a sub-cellular structure (organelle) involved in osmoregulation. It is found predominantly in protists and in unicellular algae.

Pinocytosis, otherwise known as cell drinking fluid endocytosis, and bulk-phase pinocytosis, is a mode of endocytosis in which small particles are brought into the cell, forming an invagination, and then suspended within small vesicles.

A vacuole is a membrane-bound organelle which is present in all plant and fungal cells. A vacuole is surrounded by a membrane called the tonoplast.

David Robertson suggested that all the cellular membranes share a similar underlying structure are the unit membranes.

The glycocalyx is a glycoprotein-polysaccharide covering that surrounds the cell membranes of some bacteria, epithelia and other cells.

The thickness of the plasma membrane is 70-100 A.

Chloroplast is a double membrane cell organelle found in plants.

Messenger RNA (mRNA) is a large family of RNA molecules that convey genetic information from DNA to the ribosome, where they specify the amino acid sequence of the protein products of gene expression.

Cell wall is considered to be permeable.

Euchromatin is a lightly packed form of chromatin (DNA, RNA and protein) that is enriched in genes ,and is often (but not always) under active transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus. 92% of the human genome is euchromatic. All the statements given above are correct.

One of the key organelles involved in digestion and waste removal is the lysosome. Lysosome has one membrane or single membrane.

This protoplasm is of a living plant or bacterial cell whose cell wall has been removed.

Microtubules, microfilaments and endoplasmic reticulum all form a part of cytoskeleton.

The chromatosome is a structural unit of chromatin which contains a histone octamer and one linker histone molecule (H5, H1a or H1b in chicken erythrocytes) bound to 168 bp of DNA (core particle DNA extended by 22 bp).

A microbody is a type of organelle that is found in the cells of plants, protozoa and animals. Organelles in the microbody family include peroxisomes, glyoxysomes, glycosomes and hydrogenosomes. In vertebrates, microbodies are especially prevalent in the liver and kidney organs.

The mature red blood cell contains no internal membranous structures. The mature cell has no nucleus and no organelles. As red blood cells develop and mature in bone marrow, the nucleus and organelles completely deteriorate.

The cell wall forms outside the plasma membrane initially as a thin primary cell wall. Thereafter, the primary cell wall may thicken or a more durable secondary cell wall can form between the primary cell wall and plasma membrane. All the above given structures have primary cell wall.