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Assessment Test

Crossing over and independent assortment

crossing over and independent assortment promote genetic variation.
Crossing over: two chromosomes exchange fragments; occurs between homologous chromosomes (Prophase 1).
Independent Assortment: refers to the random assignment of pairs of chromosomes.

Define Mitosis

mitosis is a multiphase process in which the nucleus of the cell divides. During mitosis, the nuclear membrane breaks down and later reforms. The chromosomes are sorted and separated to ensure that each daughter cell receives a complete set of chromosomes. (Interphase, prophase, prometaphase, metaphase, anaphase, telophase)

Define the term Gamete and explain why meiosis is necessary to maintain proper chromosome number after fertilization

gametes: produced in cells located in the germ line, either sperm or egg cells. Meiosis is a special type of nuclear division which segregates one copy of each homologous chromosome into each new gamete

Cell cycle

life story of a cell; new cell metabolizes, grows, develops and divides (mother cell) to produce two cells (daughter cells) that undergo additional cycles (clone=population of genetically identical cells)

describe mitosis in terms of daughter cells that result after that parent cell divides and in terms of the number of chromosomes in each resulting daughter cell

mitosis is essentially a duplication process: it produces two genetically identical daughter cells from a single parent cell. Mitosis replaces cells lost through everyday wear and tear; keeps tissues and organs in good working order. results in two daughter cells that have two pairs of chromosomes (46 total)

state the function of mitosis and distinguish it from cell division

mitosis is a duplication process which splits the nucleus of a parent cell, producing two genetically identical daughter cells from the parent cell. Mitosis replaces cells lost through everyday wear and tear. each daughter cell has two pairs (46) chromosomes. Mitosis keeps tissues and organs in good working order

Define Meiosis

meiosis is part of the sexual reproduction process because gametes (sperm, eggs) have 1/2 the chromosomes as diploid (2N) individuals. Meiosis functions to reduce the number of chromosomes to 1/2. each daughter cell that is produced will have 1/2 as many chromosomes as the parent cells.
Meiosis 1: number of cells double, chromosomes are reduced from 46 (whole) to 23 (half)
Meiosis 2: similar to mitosis, chromosomes are not reduced

phases of mitosis

1. Interphase
DNA has replicated, but has not formed the condensed structure of chromosome. They remain as loosely coiled chromatin.The nuclear membrane is still intact to protect the DNA molecules from undergoing mutation.
2. Prophase
The DNA molecules progressively shorten and condense by coiling, to form chromosomes. The nuclear membrane and nucleolus are no longer visible.
The spindle apparatus has migrate to opposite poles of the cell..
3. Metaphase
The spindle fibres attach themselves to the centromeres of the chromosomes and align the the chromosomes at the equatorial plate.
4. Anaphase
The spindle fibres shorten and the centromere splits, separated sister chromatids are pulled along behind the centromeres.
5. Telophase
The chromosomes reach the poles of their respective spindles. Nuclear envelope reform before the chromosomes uncoil. The spindle fibres disintegrate.
6. Cytokinesis
This is the last stage of mitosis. It is the process of splitting the daughter cells apart. A furrow forms and the cell is pinched in two. Each daughter cell contains the same number and same quality of chromosomes.

What is lactic acid fermentation

It's not the citric acid cycle. Occurs after glycolysis whenever oxygen is not present in the cell's environment. Produces less ATP than aerobic pathways. Carried out by bacteria. Electron transfer chain is in bacterial plasma membrane. Final election acceptor is a compound from environment (such as nitrate) not oxygen

Name the location in the cell where the citric acid cycle occurs and identify the products of the citric acid cycle

the citric acid cycle occurs in the mitochondrion; products: → CoA-SH + 3 NADH + 3 H+ + QH2 + GTP + 2 CO2

define electron transport chain

An electron transport chain (ETC) couples electron transfer between an electron donor (such as NADH) and an electron acceptor (such as O2) with the transfer of H+ ions (protons) across a membrane. The resulting electrochemical proton gradient is used to generate chemical energy in the form of adenosine triphosphate (ATP). Electron transport chains are the cellular mechanisms used for extracting energy from sunlight in photosynthesis and also from redox reactions, such as the oxidation of sugars (respiration).

Define Oxidative Phosphorylation

Oxidative phosphorylation is the production of ATP using energy derived from the transfer of electrons in an electron transport system (def) and occurs by chemiosmosis. Final stage of aerobic respiration

Define citric acid cycle

The citric acid cycle, also known as the Krebs cycle or tricarboxylic acid (TCA) cycle, is a series of chemical reactions in the cell that breaks down food molecules into carbon dioxide, water, and energy. In plants and animals, these reactions take place in the mitochondria of the cell as part of cellular respiration. Many bacteria perform the citric acid cycle too, though they do not have mitochondria so the reactions take place in the cytoplasm of bacterial cells. The overall reaction for the citric acid cycle is:
Acetyl-CoA + 3 NAD+ + Q + GDP + Pi + 2 H2O --> CoA-SH + 3 NADH + 3 H+ + QH2 + GTP + 2 CO2

What are the reactants and products of glycosis?

Glycolysis literally means "splitting sugars." In glycolysis, glucose (a six carbon sugar) is split into two molecules of a three-carbon sugar. Glycolysis yields two molecules of ATP (free energy containing molecule), two molecules of pyruvic acid and two "high energy" electron carrying molecules of NADH. Glycolysis can occur with or without oxygen. In the presence of oxygen, glycolysis is the first stage of cellular respiration. Without oxygen, glycolysis allows cells to make small amounts of ATP. This process is called fermentation.

Describe the role of ATP in energy transfer

ATP, or adenosine triphosphate, is the energy currency of the cell. Cells use this molecule to provide energy for numerous cellular processes such as RNA replication and the creation, or synthesis, of various molecules.

define cellular respiration

Cellular respiration is the set of the metabolic reactions and processes that take place in the cells of organisms to convert biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products. The reactions involved in respiration are catabolic reactions that involve the redox reaction (oxidation of one molecule and the reduction of another). Respiration is one of the key ways a cell gains useful energy to fuel cellular changes.

Describe how the structure of the plasma membrane relates to the permeability of substances

Plasma membrane is selectively permeable; it allows some substances to pass through, but prevents the passage of other substances; allows certain molecules or ions to pass via diffusion

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