Funbio 4

The nuclear envelope isolates nuclear material from the cytoplasm.

The nucleus is composed of the nuclear envelope, chromatin, nucleolus, nuclear pores, and nucleoplasm.

The nuclear lamina provides structural support to the nuclear envelope and aids in positioning nuclear pores.

<p>Nuclear pores regulate the exchange of materials between the nucleus and the cytoplasm.</p> Signup and view all the answers

<p>Genetic mutations in the nuclear lamina can cause progeria syndrome and Emery-Dreifuss muscular dystrophy (EDMD).</p> Signup and view all the answers

<p>The nuclear pore complex primarily allows the transport of water-soluble molecules across the nuclear envelope.</p> Signup and view all the answers

<p>The nuclear pore complex consists of eight subunits that surround a central channel approximately 9nm in diameter.</p> Signup and view all the answers

<p>Nucleoplasm is a highly viscous liquid that surrounds the chromosomes and nucleoli in the nucleus, containing dissolved substances like nucleotides and enzymes.</p> Signup and view all the answers

<p>A nucleoside consists of a purine or pyrimidine base linked to a sugar, whereas a nucleotide includes one or more nucleosides bonded to a phosphate group.</p> Signup and view all the answers

<p>The network of fibers in the nucleoplasm is referred to as the nuclear matrix.</p> Signup and view all the answers

<p>They are usually folded into an alpha-helix or can be arranged in a beta-barrel structure.</p> Signup and view all the answers

<p>Peripheral proteins temporarily interact with integral membrane proteins and associate with the lipid bilayer's peripheral regions.</p> Signup and view all the answers

<p>They readily pass through the membrane due to its semi-permeable nature.</p> Signup and view all the answers

<p>The nucleus controls genetic information, heredity characteristics, and the synthesis of proteins and enzymes.</p> Signup and view all the answers

<p>Integral membrane proteins are permanently attached to the membrane and cannot be easily removed, while peripheral proteins are temporarily associated.</p> Signup and view all the answers

<p>They have specialized functions that require more space for hemoglobin and other cellular components, thus limiting their futures.</p> Signup and view all the answers

<p>They facilitate the movement, as the rates of diffusion for these molecules cannot be explained solely by passive transport.</p> Signup and view all the answers

<p>Charged inorganic ions and larger polar molecules typically need channels or carriers for movement across the membrane.</p> Signup and view all the answers

<p>The plasma membrane consists of a lipid bilayer with embedded proteins that can move laterally, creating a fluid structure.</p> Signup and view all the answers

<p>Integral membrane proteins are embedded within the lipid bilayer, while peripheral proteins are attached to the outer or inner surface of the membrane.</p> Signup and view all the answers

<p>Membrane proteins facilitate the selective transport of substances across the membrane and assist in cell signaling.</p> Signup and view all the answers

<p>The nucleus is surrounded by a nuclear envelope, contains pores for transport, and is filled with karyoplasm.</p> Signup and view all the answers

<p>Euchromatin is less condensed and active in transcription, while heterochromatin is densely packed and generally inactive.</p> Signup and view all the answers

<p>Each eukaryotic organism has a characteristic number of chromosomes that is consistent for that species.</p> Signup and view all the answers

<p>The plasma membrane appears between 7.5 – 10 nm in diameter under electron microscopy.</p> Signup and view all the answers

<p>Saturated fatty acids in the outer face of the membrane contribute to its structural integrity and fluidity.</p> Signup and view all the answers

<p>The glycocalyx protects the cell and may facilitate cell recognition and communication.</p> Signup and view all the answers

<p>Amphipathic molecules, with hydrophobic tails facing inwards and hydrophilic heads facing outwards, allow the bilayer to form naturally.</p> Signup and view all the answers

<p>The nucleolus is primarily responsible for transcribing ribosomal RNA (rRNA) and assembling ribosomal particles.</p> Signup and view all the answers

<p>The size of the nucleolus reflects the activity level of the cell; it may be small or occupy up to 25% of the nucleus depending on rRNA synthesis demands.</p> Signup and view all the answers

<p>Nucleolar organizer regions (NORs) are essential chromosomal regions crucial for nucleolus formation.</p> Signup and view all the answers

<p>Down's syndrome is caused by trisomy 21, which is the presence of an extra copy of chromosome 21.</p> Signup and view all the answers

<p>Ribosomes, which are formed from rRNA and proteins, are produced in the nucleolus and are essential for protein synthesis in the cell.</p> Signup and view all the answers

<p>Chromatin fibers are collections of threads and fibers present in the nucleoplasm during interphase, which can be observed using an electron microscope.</p> Signup and view all the answers

<p>Euchromatin is lightly packed, allows DNA transcription, while heterochromatin is tightly packed, does not undergo transcription, and serves functions like gene regulation.</p> Signup and view all the answers

<p>A nucleosome is the basic unit of chromatin, consisting of a DNA double helix wound around a histone protein, critical for the compact packing of DNA in chromosomes.</p> Signup and view all the answers

<p>Diploid cells contain two sets of chromosomes (2N), while haploid cells contain one set (N). For example, humans have 46 chromosomes (2N) and gametes have 23 chromosomes (N).</p> Signup and view all the answers

<p>The histone octamer is a protein complex around which DNA winds to form nucleosomes, playing a crucial role in chromatin organization and gene regulation.</p> Signup and view all the answers

<p>During cell division, each chromatid is a mirror image of its sister, ensuring that each daughter cell receives an identical set of chromosomes.</p> Signup and view all the answers

<p>The dense packing of heterochromatin limits access to DNA, thereby regulating gene expression and protecting chromosomal integrity.</p> Signup and view all the answers

<p>During interphase, the chromatin is less coiled, forming fibers that become visible under an electron microscope, facilitating cellular functions like transcription.</p> Signup and view all the answers