What best distingishes living things from nonliving matter?
The ability of organisms to produce more of their own kind
Reproduction of cells
What does cell division enable multicellular eukaryotes to do?
Develop from a single cell and once fully grown, to renew, repair, or replace its cells as needed
The life of a cell from formation to its own division
Most cell divions result in
The distribution of identical genetic material-DNA-to two daughter cells
DNA is passed from one generation of cells to the next with?
All of the DNA in a cell
What can a genome consist of?
A single DNA molecule which is common in prokaryotic cells, or a number of DNA molecules which is common in eukaryotic cells
DNA molecules in a cell are packaged into this
Eukaryotic chromosomes consist of what?
A complex of DNA and protein
Nonreproductive cells that have two sets of chromosomes
Sex cells that have one set of chromosomes
What happens in preparation for cell division?
DNA is replicated and the chromosomes condense
Each duplicated chromosome has two sister chromatids... what are those?
Joined identical copies of the orignal chromosome
Where the two chromatids are most closely attached
What happens to the two sister chromatids during cell division?
The two sister chromatids of each duplicated chromosome separate and move into two nuclei and once they are seperate, the chromatids are called chromosomes
What does eukaryotic cell division consist of?
Mitosis and cytokinesis
The division of the genetic material in the nucleus
The division of the cytoplasm
what are gametes produced by?
What does meiosis yield?
Nonidentical daughter cells that have only one set of chromosomes, half as many as thhe parent
What two pahses alternate?
The mitotic phase alternates with interphase in the cell cycle
What two phases does the cell cycle consist of?
The Mitotic phase including mitosis and cytokinesis and the
Interphase which includes cell growth and copying of chromosomes in preparation for cell division
About 90% of the cell cycle can be divided into subphases
What are the three phases of interphase?
G1 phase, G2 phase, S phase
Although the cells grow during all three phases, what phase are chromosomes duplicated strictly in?
The S phase
What five phases is mitosis divided into?
Prophase, metaphase, anaphase, telophase
Structure made of microtubules and associated proteins which controls movement during mitosis
In animal cells, where does the assembly of spindle microtubules begin?
In the centrosome which is the microtubule organizing center
A bunch of sister chromatids just hanging out
radial array of short microtubules that extends from each centrosome
Some spindle microtubules attach to the kinetochores of chromsomes and begin to move the chromosomes
Protein complexes that assemble on sections of DNA at a centromere
The centromeres of all the chromosomes are at the metaphase plate which is an imaginary structure at the midway point between the spindle's two poles
Sister chromatids seperate and move along the kinetochore microtubules towards opposite ends of the cell
What are chromosmes reeled in by in anaphase?
Motor proteins at spindle poles
How does the cell elongate during mitosis?
Nonkinetochore micrtubules from opposite poles overlap and push against each other
What happens at the end of anaphase?
Dulpicate groupds of chromosomes have arrived at opposite ends of the elongated parent cell and cytokinesis begins during anaphase or telophase and the spindle eventually dissasembles
How does cytokinesis form in animal cells
By cleavage forming a cleavage furrow
What forms in plants during cytokinesis?
What is the eukaryotic cell cycle regulated by?
A molecular control system that varies with each type of cell
Sequential events of the cell cycle are directed by what?
A distinct cell cycle control system which is similar to a timing device of a washing machine
Where the cell cycle stops until a go-ahead signal is recieved
What checkpoint is the most important?
Set of regulatory proteins and protein complexs that regulate the cell cycle
density dependent inhbition
Crowded cells stop dividing
Where animal cells must be attached to a substratum in order to divide
Cancer cells quick points
-Do not respond to sgnals that nromally regulate the cell cycle
-May ned growth factors to grow and divide
-Make their own growth factor
-Convey a growth factor's signal without the presence of the growth factor
-May have an abnormal cell cycle control system
When a normal cell is converted to a cancerous cell
Cancers that are not eliminated by the immune system form what?
Tumors, masses of abnormal cells within otherwise normal tissue
An abnormal cell remaining at original site
Invade surrounding tissues and can metastasize exporting cancer cells to other parts of the body where they form additional tumors
What best describes the relationship between photosynthesis and respiration?
Photosynthesis stores energy in complex organic molecules, whereas respiration releases it
Generation of proton gradients across membranes occurs during
bot photosynthesis and respiration
Reactions that require CO₂ take place in
Where does the Calvin cycle take place?
Stroma of the chloroplast
If the power fails and the lights go dark, what will happen to CO₂ levels?
CO2 will rise as a result of both animal and human respiration
Where are the molecules of the electron transport chain found in plant cells?
Thylakoids in the chloroplast
Which of the following are directly associated with photosystem I?
Recieving electrons from the thylakoid membrane ETC
A plant has a unique photosynthetic pigment. The leaves of this plant appear to be reddish yellow. What wavelengths of visible light are being absorbed by this pigment?
Blue and violet
Photorespiration lowers the efficiency of photosynthesis by
What wavelength of light in the figure is most effective in driving photosynthesis?
Which of the following statements is a correct distinction between autotrophs and heterotrophs?
Autotrophs, unlike heterotrops have the ability to nourish themselves beginning with CO2 and other inorganic nutrients
Which of the following are products of the light reactions of photosynthesis that are utilized in the Calvin cycle?`
ATP and NADPH
In autotrophic bacteria, where are the enzymes located that can carry on carbon fixation (reduction of carbon dioxide to carbohydrate)?
In the cytosol
What is the primary function of the Calvin cycle?
synthesize simple sugars from CO2
Some photosynthetic bacteria (e.g., purple sulfur bacteria) have only photosystem I, whereas others (e.g., cyanobacteria) have both photosystem I and photosystem II. Which of the following might this observation imply?
Photosystem I photosynthesis is more ancestral
In the process of carbon fixation, RuBP attaches a CO₂ to produce a six-carbon molecule, which is then split to produce two molecules of 3-phosphoglycerate. After phosphorylation and reduction produces glyceraldehyde 3-phosphate (G3P), what more needs to happen to complete the Calvin cycle?
regeneration of NAD+
Where do the enzymatic reactions of the Calvin cycle take place?
stroma of the chloroplast
CAM plants keep stomata closed in daytime, thus reducing loss of water. They can do this because they
Fix CO2 into organic acids throughout the night
What does the chemiosmotic process in chloroplasts involve?
establishment of proton gradient across the thylakoid membrane
Plants photosynthesize only in the light. Plants respire
both in the light nd dark
Which of the following sequences correctly represents the flow of electrons during photosynthesis?
H2O -> NADPH -> Calvin cycle
If atmospheric CO₂ concentrations increase twofold or more, how will plants be affected, disregarding any changes in climate?
C3 plants will have faster growth an C4 plants will be minimally affected
Which of the events listed below occurs in the light reactions of photosynthesis?
light is absorbed and funneled to reaction center chlorophyll a
In thylakoids, protons travel through ATP synthase from the thylakoid space to the stroma. Therefore, the catalytic "knobs" of ATP synthase would be located
Facing the stroma
The splitting of carbon dioxide to form oxygen gas and carbon compounds occurs during
Niether photosynthesis or repiration
Which of the following does not occur during the Calvin cycle?
Release of oxygen
The alternative pathways of photosynthesis using the C₄ or CAM systems are said to be compromises. Why?
Both minimize photosynthesis but expend more ATP during carbon fixation
78) A particular cell has half as much DNA as some other cells in a mitotically active tissue. The cell in question is most likely in
74) One difference between cancer cells and normal cells is that cancer cells
Continue to divide even when tightly packed together
16) For anaphase to begin, which of the following must occur?
Cohesion must be cleaved enzymatically
10) Taxol is an anticancer drug extracted from the Pacific yew tree. In animal cells, Taxol disrupts microtubule formation by binding to microtubules and accelerating their assembly from the protein precursor, tubulin. Surprisingly, this stops mitosis. Specifically, Taxol must affect
The formation of the mitotic spinle
50) For a chemotherapeutic drug to be useful for treating cancer cells, which of the following is most desirable?
It interferes with rapidly dividing cells
11) Which of the following are primarily responsible for cytokinesis in plant cells but not in animal cells?
Golgi derived vesicles
71) When the cell has just completed telophase, which of the following does he see?
Two small cells with chromatin
9) Where do the microtubules of the spindle originate during mitosis in both plant and animal cells?
1) The centromere is a region in which
Chromatids remain attached to one another unless its anaphase
76) In the cells of some organisms, mitosis occurs without cytokinesis. This will result in
Cells with more than one nucleus
46) All cell cycle checkpoints are similar in which way?
They activate or inactivate certain proteins
23) What is a cleavage furrow?
A groove in the plasma membrane between daughter nuclei
Several organisms, primarily protists, have what are called intermediate mitotic organization.
They show some,but not all evolutionary steps to go through and complete mitosis
preliminary observations showed them that the cell line did not exhibit either density-dependent inhibition or anchorage dependence. What could they conclude right away?
They show characteristics of tumors
3) If there are 20 chromatids in a cell, how many centromeres are there?
20) During which phase of mitosis do the chromatids become chromosomes?
37) Density-dependent inhibition is explained by which of the following?
As cells become more numerous, the cell surface proteins of one cell contact the adjoining cells and they stop dividing.
6) At which phase are centrioles beginning to move apart in animal cells?
77) Which of the following does not occur during mitosis?
replication of DNA
Transmission of traits from one generation to the next
Demonstarted by the diferences in appearance that ofspring sow from parents and siblngs
The study of heredity and variation
The units of heredity and are made of segments of DNA
Ofsspringfpring acquire genes from?
Parents by inheriting chromosomes
How many somatic cells do humans have?
46 chromomes or 23 pairs
Two chromosomes in each pair and they are the same length, and shapre and carry genes controlling the same inherited characters
How many autosomes are there?
Gamete (sperm and egg) contains what?
A single set of chromosomes and is haploid
Human haploid number
How are gametes produced?
What alternate in sexual life cycles?
Meiosis and fertilization
Plants and some algae undergo an alternation of generation
This life cycle contains both diploid and haploid multicellular stage and the diploid organism called the sporophyte makes haploid spores by meisois
What kind of cells undergo meiosis?
Since meiosis undergoes two sets of clel divisions unlike mitosis, what is the end result?
Four daughter cells instead of two
First half of meiotic divison
Homologous paris of chromosomes pair and seperate
Second half of meitotic division
Sister chromatids of each chromosome seperate
Occupies more than 90% of the time required for meiosis
Chromosomes begin to condense
Crossing over occurs
Chromosomes line up atthe metaphase plate, with one chromosome facing each pole
Pairs of homologous chromosomes seperate and move towards each pole
Each half of the cell has a haploid set of chromosomes; each chromosome still consists of two sister chromatids
Meiosis II is very similar to mitosis and occurs in the same four phases
A spindle apparatus forms then chromosomes move towards the meta phase plate
Sister chromatids are rearranged at the metaphase plate
At the end of meiosis
There are four daughter cells, each with a haploid set of unduplicated chromosomess
Three events that are unique to meiosis
Synapsis and crossing over in prophase I this is where chromosomes physically connect and exchange informtion
Homologous pairs at the metaphase plate: homologous pairs of chromosomes are positioned in metaphase I
Seperation of homologs during anaphase I
What is the original source of genetic diversity?
Three mechanisms that contribute to genetic variation
-Independent assortment of chromosomes
Main site of photosynthesis
Where are chloroplats mainly found?
In the mysophyll
6CO2 + 12H2O -> C6H12O6 + 6H2O + ^O2
What is reduced in photosynthesis?
What is oxidized in photosynthesis?
Where do light reactions occur?
In the thylakoids
Where does the calvin cycle take place?
In the stroma