Answer:
There are prion-like particles in the brain normally, and when these become abnormal they can cause disease. (Ans. A)
Explanation:
Prions are proteins which can trigger normal proteins to fold abnormally, and they are present in the brain. They are causing many types of neurodegenerative diseases in both humans and animals. Which are known as transmissible spongiform encephalopathies.
Prions can enter the brain with the help of infection, also can arise from the gene mutation that encodes the proteins, and sometimes this affects humans by infected meat.
If a person infected from prion disease, it affects central nervous system tissues like brain, eye tissues and spinal cord.
Answer:
When a leaf is placed in a solution whose salt concentration is higher than the salt concentration of the leaves, the water with in the leaves shall move out of the leaves due to the osmotic pressure gradient. This will cause the plant cell devoid of water thereby leading them to shrink and wilt.
Explanation:
Answer: the correct answer is A) All plants should be the same age and health and be given equal amounts of water and sunlight.
Answer:
C, a long absolute refractory period.
Explanation:
Tetanus is not possible in cardiac muscle tissue because cardiac cells have longer action potentials and a very long refractory period compared to other cells. This helps prevent the heart from cramping and seizing up.
Answer: Question 1 answer: Skin cells continually replicate
Explanation: The cells in the superficial or upper layers of skin, known as the epidermis, are constantly replacing themselves. This process of renewal is basically exfoliation (shedding) of the epidermis. But the deeper layers of skin, called the dermis, do not go through this cellular turnover and so do not replace themselves.
Question 2 answer: Heart cells undergo terminal differentiation
Explanation: Different cell types (e.g., neurons, skeletal and heart myocytes, adipocytes, keratinocytes) undergo terminal differentiation, in which acquisition of specialized functions entails definitive withdrawal from the cell cycle.
Question 3 answer: DNA replicates in the nucleus
Explanation: DNA replication occurs in the cytoplasm of prokaryotes and in the nucleus of eukaryotes. Regardless of where DNA replication occurs, the basic process is the same. The structure of DNA lends itself easily to DNA replication.
Question 4 answer: The ability to reverse terminal differentiation might affect gene expression in a complex organism
Question 5 answer Cytoplasm replicates during mitosis
Explanation: This process involves replication of the cell's chromosomes, segregation of the copied DNA, and splitting of the parent cell's cytoplasm. ... The outcome of binary fission is two new cells that are identical to the original cell.
