Hydrophobic signal molecules typically ...     a)  bind to receptor proteins in the cytosol.   b)  bind to plasma membrane receptors then move inside the cell.   c)  activate pathways that drive gene transcription.   d)  a and c   e)  a, b and c

Aging can be caused by   Question 12 options:   a)  the damage caused by free radicals.   b)  shrinking telomeres.   c)  choice "A" and choice "B" and other factors.   d)  neither choice "A" nor choice "B."

Typically, our cells have a high concentration of sodium ions outside and a low concentration of sodium ions inside. As sodium ions continue to move out of the cell, the protein that they travel through is called a: a) carrier b) pump c)channel d) vesicle e) aquaproin

29 Which kind of macromolecule is regarded as a good candidate for the original self-replicator (or genetic molecule)  because it can both cause dehydration synthesis and encode information efficiently? a) Neurotransmitter                     b) DNA               c) Hormones                       d) Proteins             e) RNA

34- What is the function of the cytoplasmic streaming in a cell? a) Cellular respiration b) Cellular communication c) Cell division d) Movement of organelles and nutrients within the cell 35- Which organelle is responsible for regulating the levels of calcium ions in a cell? a) Nucleus b) Golgi apparatus c) Endoplasmic reticulum d) Mitochondria 36- What is the function of the peroxisome in a cell? a) Synthesis of lipids b) Detoxification of harmful substances c) Protein synthesis d) Storage of genetic information ۷۵ / ۱۳ 37- Which organelle is responsible for the synthesis of RNA molecules? a) Nucleus b) Ribosome c) Golgi apparatus d) Vacuole 38- What is the function of the cytoplasmic vesicles in a cell? a) Energy production b) Transport of molecules within the cell c) Intracellular digestion d) Synthesis of proteins

6. Which of the following proteins does not function in cell-cell interaction? a) Cadherin b) Cytochrome c c) Integrin d) N-CAM

6.

What integral membrane protein family made of two membrane-spanning chains (α and β) is involved in attaching cells to their extracellular microenvironment? a)     lamininsb)     fibronectinsc)     integrinsd)     myosinse)     lysins

Imagine you are working in a lab and you examine an unknown cell only to discover it possesses gap junctions and microvilli. Based on those findings, what can you assume regarding its function(s)? O a) it specializes in intercellular communication O b) it can withstand mechanical stress c) it likely functions in absorption O d) A and C O e) B and C

Answer the Guide Question: a) Each cell in an organism has all of the basic parts. Each has a function that benefits the other cells, how might the presence of different cell structures in plant and animal help them perform their functions as an organism. Explain. b) Why is the cell membrane considered as the guard of the cell? c) Why is the lysosome considered as the suicide bag of the cell?