Question

59. If "O" is the gene for the color of a carrot, and "OO" is the written form of the genotype, what is the genotype? a. orange b. heterozygous dominant c. homozygous recessive d. homozygous dominant e. heterozygous recessive

When you pour salt on a snail or slug, they begin to shrivel up and die while excreting a bubbly mucus around themselves, what process best describes what is happening to the snail? a. Osmosis b. Endocytosis c. Passive Facilitated Diffusion d. Passive Simple Diffusion e. Active Transport

What attracts or directs the synthesis enzyme to the template in Transcription? a. Promoter b. 5'-cap c. Poly-A Tail d. Start Codon e. Primer

Thinking of the various molecules that make up a biological membrane, the nature of which molecule specifically provides membranes with its unique structure (the bilipid layer)? a. proteins b. phospholipids c. carbohydrates d. cholesterol e. cellulose

70. Why is the cytoskeleton and ribosomes characterized as cellular structures rather than organelles? a. they lack a cell wall b. they lack a nucleus c. they lack a biological membrane d. they are characterized as vacuoles, not structures e. they lack nucleotides

73. Which of the following is NOT a function of cellular membranes? a. regulate transport of a solute b. localize function c. define compartments d. mediate cell-to-cell communication e. locomotion

Answer 1

A. Homozygous Dominant

There are two alternative forms of an allele, dominant and recessive, dominant usually denoted by capital letter and recessive by a lower case letter.

Genotype in which two identical i.e. either dominant or recessive alleles are present are homozygous, and in which a combination of dominant and recessive alleles is present are heterozygous.

As O depicts the gene for colour,

OO - homozygous dominant

oo - homozygous recessive

Oo - heterozygous

B. (a) Osmosis

When salt is added to snail or slug, water from their cells is pulled out due to osmosis and after shrinkage they produce a slimy layer around themselves for protection. Air is released from their cells during shrinkage/ shriveling which causes bubbling of slime.

C.(a) Promoter

Transcription is the process in which RNA synthesis from DNA template takes place. RNA polymerase (Synthesis enzyme) begins RNA synthesis when it binds to the promoter sequence ( A stretch of DNA sequence which acts as binding sites for proteins which initiate transcription).

D.(b) phospholipids

Lipid bilayer is polar in nature, phospholipids are responsible for the unique structure of the plasma membrane as phospholipids contain a hydrophilic head and the hydrophobic tail, the hydrophilic head faces at the surface and hydrophobic tails form the inner part.

E.(b) they lack a biological membrane

An organelle is defined as a structure enclosed by a biological membrane and is responsible for specific function. Cytoskeleton forms the structural framework of the cell and ribosomes are also not membrane enclosed, therefore these structures are not considered as organelles.

F.(e) locomotion

Cell membrane is semi permeable and hence regulates movement of solutes, biomolecules present on cell membrane surface regulate localisation (trafficking) of molecules, mediates cell-cell communication and forms a boundary for compartmentalization.

Cell membrane was thought to be responsible for ameboid movement but recently it has been reported that cell membrane does not moves forward during ameboid movement rather it is formed in front de Novo and the one left behind is dissolved in cytoplasm.