BIOLOGY PROCTORED EXAM PENN FOSTER -

BIOLOGY PROCTORED EXAM PENN FOSTER -

ACTUAL EXAM/PENN FOSTER BIOLOGY PROCTORED

EXAM LATEST 200 QUESTIONS AND CORRECT

ANSWERS(VERIFIED ANSWERS )|AGRADE

Explain the process of diffusion: - ANSWER- Molecules move from an area of

higher concentration to an area of lower concentration until the concentration of molecules is the same at both sites

Explain the process of osmosis: - ANSWER- Water moves from areas of low

solute concentration to areas of high solute concentration

Describe a basic enzymatic reaction: - ANSWER- S+E= P+E

E represents the enzyme catalyzing the reaction S is the substance being changed P is the product of the reaction

What is an enzyme? - ANSWER- Catalysts that increase the speed of a chemical reaction without undergoing any permanent chemical change

What is the process of photosynthesis? - ANSWER- -The process in which the Sun's energy is converted into chemical energy (occurs in chloroplasts).-Carbon dioxide and water are added -Sugar and oxygen are produced

What is cellular respiration? - ANSWER- Cellular respiration is the process that releases energy from food in the presence of oxygen.

What is the cellular respiration equation? - ANSWER- 6O2 + C6H12O6 -> 6CO2

• 6H2O + Energy

What is glycolysis? - ANSWER- "splitting sugars." yields two molecules of ATP.

What is Krebs cycle? - ANSWER- This term refers to a series of chemical reactions that involve the complete oxidation of acetyl CoA and produce 2 mol of ATP (energy) along with hydrogen and carbon, which combine with oxygen to form (H2O) and (CO2).

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What is the electron transport chain? - ANSWER- Is a sequence of electron carrier molecules that shuttle electrons, down a series of reactions that release energy; used to make ATP.

What is cellular reproduction? - ANSWER- Process by which cells divide to form new cells

Growth phase- cell duplicates its contents and DNA Cell Division- the cytoplasm and DNA of a parent cell are distribute to 2 daughter cells

How many chromosomes do humans have? - ANSWER- 46 (23 pairs)

What is nondisjunction and when does it occur? - ANSWER- Nondisjunction occurs when chromosomes do not separate properly during cell division. This can form a gamete with an extra chromosome or one missing part or all of a chromosome (aka monosomy or trisomy). OCCURS DURING ANAPHASE 1 & 2

What is the law of dominance? - ANSWER- Mendel's 2nd law of inheritance - one gene usually expresses itself over the other (one gene is dominant over the other)

What is the law of segregation? - ANSWER- during the production of gametes the two copies of each hereditary factor segregate so that offspring acquire one factor from each parent

What is the law of independent assortment? - ANSWER- Genes for different traits are inherited independently of each other

What is DNA biotechnology and what are some issues? - ANSWER- Use of natural biological systems to create a product or achieve some other end desired by humans

Issues:

-People feel it goes against the laws of nature -People worry about the safety of it

How can lack of genetic control lead to cancer? - ANSWER- When someone has inherited an abnormal copy of a gene, their cells already start out with one mutation. This makes it easier for enough mutations to build up for a cell to become cancer

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G1 (Growth 1) - ANSWER- Cell volume doubles and organelles replicate

S phase (synthesis) - ANSWER- DNA is replicated

G2 phase - ANSWER- cell produces proteins necessary for mitosis and then prepares to divide

What are the stages of mitosis? - ANSWER- prophase= chromosomes become visible as paired chromatids and the nuclear enveloped disappears

metaphase= the chromosomes are aligned at the spindle equator midway between the spindle poles

anaphase= sister chromatids separate and become daughter chromosomes- each pole receives a set of daughter chromosomes

telophase= spindle disappears as new nuclear envelopes form around the daughter chromosomes- each nucleus contains the same number and kinds of chromosomes the original parent nucleus

Describe the purpose of the cell cycle control system - ANSWER- Series of checkpoints to make sure that everything is proceeding properly. Checkpoints delay development from one phase off the cycle to the next until everything that should happen in a particular phase has happened

Explain the phases of the cell cycle control system: - ANSWER- G1= cell can

enter GO or under apoptosis if DNA is damaged beyond repair. If the cell cycle passes his checkpoint, the cell is committed to complete the cycle G2= the cell checks to make sure DNA has been replicated properly M Checkpoint= cell makes sure the chromosomes are properly aligned and ready to be partitioned to the daughter cells

What is apoptosis? - ANSWER- Programmed chemical process that causes a cell to self-destruct

Serves the purpose of keeping the number of cells in the body roughly constant and removing cells with damaged DNA

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Explain the basics of mitosis - ANSWER- Type of cell division in which one cell(the mother) divides to produce 2 new cells(the daughters) that are genetically identical to itself

Somatic cells aids in the growth and development of an organism as well as in the replacement of old and injured cells

• results in 2 daughter cells that are genetically identical

Explain the basics of meiosis - ANSWER- Type of cell division in which the number of chromosome is reduced in half from the diploid number (2n) to a

haploid number (n). The result is 4 gametes: eggs in females and sperm in males

Reproductive cells produces gametes for sexual reproduction

• The gametes contain half the number of chromosomes as the parent cell

What are the stages of meiosis I? - ANSWER- Interphase: DNA in the cell is

copied resulting in 2 identical full sets of chromosomes

Prophase 1: the copied chromosomes condense into x shaped structure- each

chromosome is composed of 2 sister chromatids Metaphase 1: chromosome pairs line up next to each other along the center of the cell

Anaphase 1: pair of chromosomes are pulled apart, pull one chromosome to each

pole

Telophase 1: chromosomes complete their move to opposite poles of the cell- 2

nuclei form

What are the stages of meiosis II? - ANSWER- Prophase II: 2 daughter cells, each with 23 chromosomes

• membrane around the nucleus in each daughter cell dissolves away releasing

chromosomes

Metaphase II: 2 daughter cells in chromosomes line up end-to-end along the

equator of the cell Anaphase II: Sister chromatids are then pulled to opposite poles due to the action of the meiotic spindle- separated chromatids are now individual chromosomes

Telophase II: Chromosomes complete their move to the opposite poles of the cell

• Membrane forms around each set of chromosomes to create 2 new cell nuclei

What is the structure and function of DNA? - ANSWER- Long chain of repeating units called nucleotide that consist of 2 strands that spiral around each other in a structure called double helix

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