Ons of
bodo
fused
come
1 why is the phospholipid bilayer only partially permeable to water?
water is repelled by the polar tails of the phospholipid.
water is repelled by the polar head of the phospholipid.
water is repelled by the hydrophobic tails of the phospholipid
d water is repelled by the hydrophobic head of the phospholipid

The correct option is C) Water is repelled by the hydrophobic tails of the phospholipid.

Explanation:

The cell membrane is made up of phospholipids. The phosphates make up the head  and are hydrophilic. The lipids make up the tail and re hydrophobic. The cell membrane is double layered with the heads pointing outwards and the tails embedded inwards. As lipids do not dissolve in water, hence the cell membrane is partially permeable for water. The tails made up of lipids are hydrophobic and hence repel water.

fertilization, pictured in figure 24.23a is the process in which gametes (an egg and sperm) fuse to form a zygote. the egg and sperm each contain one set of chromosomes. to ensure that the offspring has only one complete diploid set of chromosomes, only one sperm must fuse with one egg. in mammals, the egg is protected by a layer of extracellular matrix consisting mainly of glycoproteins called the zona pellucida. when a sperm binds to the zona pellucida, a series of biochemical events, called the acrosomal reactions, take place. in placental mammals, the acrosome contains digestive enzymes that initiate the degradation of the glycoprotein matrix protecting the egg and allowing the sperm plasma membrane to fuse with the egg plasma membrane, as illustrated in figure 24.23b. the fusion of these two membranes creates an opening through which the sperm nucleus is transferred into the ovum. the nuclear membranes of the egg and sperm break down and the two haploid genomes condense to form a diploid genome.

explanation:

both anaerobic and aerobic respiration use glucose (or other carbohydrates), proteins and lipids to produce atp and nadh. cell uses those energy molecules, obtained from food and   breaks them down during the chemical reactions of respiration. in anaerobic respiration, nadh is regenerated to nad+ by enzymes lactate dehydrogenase (lactate is produced, e.g. in muscle cells) or by alcohol dehydrogenase where ethanol is produced (alcohol fermentation), while in aerobic respiration, electrons from nadh are deposited in the mitochondria to regenerate nad+ (electron transport chain. anaerobic respiration produces 2 atp per molecule of glucose compared to aerobic respiration where about 38 atp molecules are produced.