BSC 310 Lecture Notes - Lecture 15: Microbiological Culture, Biochemical Oxygen Demand, Growth Medium

12 views3 pages

silvercicada472

28 Jun 2018

School

University of Alabama

Department

BSC

Course

BSC 310

Professor

Julie Olson

For unlimited access to Class Notes, a Class+ subscription is required.

Microbial Reproduction and Growth

Reproduction patterns. During their growth cycles, microorganisms undergo

reproduction many times, causing the numbers in the population to increase

dramatically.

In fungi, unicellular algae, and protozoa, reproduction involves a duplication of the nucleus

through the asexual process of mitosis and a splitting of the cell in cytokinesis. Reproduction

can also occur by a sexual process in which haploid nuclei unite to form a diploid cell having

two sets of chromosomes. Various changes then follow to yield a sexually produced

offspring. Sexual reproduction has the advantage of mixing chromosomes to obtain genetic

variations not possible with asexual reproduction. However, fewer individuals normally

result from sexual reproduction than from asexual reproduction. More details on these

methods are provided in the chapters on fungi and protozoa.

Bacteria reproduce by the asexual process of binary fission. In this process, the

chromosomal DNA duplicates, after which the bacterial membrane and cell wall grow inward

to meet one another and divide the cell in two. The two cells separate and the process is

complete.

One of the remarkable attributes of bacteria is the relatively short generation time, the time

required for a microbial population to double in numbers. The generation time varies among

bacteria and often ranges between 30 minutes and three hours. Certain bacteria have very

brief generation times. Escherichia coli, for example, has a generation time of about 20

minutes when it is dividing under optimal conditions.

The growth curve. The growth of a bacterial population can be expressed in various phases of

a growth curve. The logarithms of the actual numbers in the population are plotted in the

growth curve along the side axis, and the time is plotted at the base. Four phases of growth

are recognized in the growth curve.

In the first phase, called the lag phase, the population remains at the same number as the

bacteria become accustomed to their new environment. Metabolic activity is taking place,

and new cells are being produced to offset those that are dying.

In the logarithmic phase, or log phase, bacterial growth occurs at its optimal level and the

population doubles rapidly. This phase is represented by a straight line, and the population

is at its metabolic peak. Research experiments are often performed at this time.

During the next phase, the stationary phase, the reproduction of bacterial cells is offset by

their death, and the population reaches a plateau. The reasons for bacterial death include

the accumulation of waste, the lack of nutrients, and the unfavorable environmental

conditions that may have developed. If the conditions are not altered, the population will

enter its decline, or death phase (Figure 1 ). The bacteria die off rapidly, the curve turns

downward, and the last cell in the population soon dies.

find more resources at oneclass.com

Unlock document

This preview shows page 1 of the document.
Unlock all 3 pages and 3 million more documents.

Already have an account? Log in

Document Summary

During their growth cycles, microorganisms undergo reproduction many times, causing the numbers in the population to increase dramatically. In fungi, unicellular algae, and protozoa, reproduction involves a duplication of the nucleus through the asexual process of mitosis and a splitting of the cell in cytokinesis. Reproduction can also occur by a sexual process in which haploid nuclei unite to form a diploid cell having two sets of chromosomes. Various changes then follow to yield a sexually produced offspring. Sexual reproduction has the advantage of mixing chromosomes to obtain genetic variations not possible with asexual reproduction. However, fewer individuals normally result from sexual reproduction than from asexual reproduction. More details on these methods are provided in the chapters on fungi and protozoa. Bacteria reproduce by the asexual process of binary fission. In this process, the chromosomal dna duplicates, after which the bacterial membrane and cell wall grow inward to meet one another and divide the cell in two.

Related Questions

Question 1 Which characteristic(s) of mitochondria andchloroplasts supports their existence as independent prokaryoticcells that were engulfed by eukaryotic cells?

Question 1 options: their size presence of their own DNA theirself-replication by binary fission all of these characteristicssupport that mitochondria and chloroplasts were independentprokaryotic cells that were engulfed by eukaryotic cells

Question 2 Mitochondria originated from __________, which wereengulfed during __________ endosymbiosis. Chloroplasts originatedfrom __________, which were engulfed during __________endosymbiosis.

Question 2 options: aerobic bacterium; primary; cyanobacteria;primary anaerobic bacterium; primary; cyanobacteria; secondarycyanobacteria; primary; aerobic bacterium; secondary cyanobacteria;primary; aerobic bacterium; primary

Question 3 Saved Secondary endosymbiosis refers to the processby which

Question 3 options: prokaryotes acquired chloroplasts.prokaryotes acquired mitochondria. eukaryotic cells engulfedcyanobacteria. eukaryotic cells with mitochondria engulfed aphotosynthetic.

Question 4 Saved Though there are exceptions, __________ is acommon reproductive strategy among protists.

Question 4 options: sexual reproduction by mitosis asexualreproduction by mitosis binary fission asexual reproduction bymeiosis

Question 5 Protists with chloroplasts are __________ that maketheir own food. Protists that lack chloroplasts ___________ and arethus heterotrophic; this group is generally known as__________.

Question 5 options: parasites; ingest food; protozoansheterotrophs; photosynthesize; plankton photosynthetic autotrophs;ingest or absorb food; protozoans green algae; are parasites;plankton

Question 6 An endosymbiotic protist that does not cause diseaseis likely

Question 6 options: plankton. a protozoan. a parasiticheterotroph. a photosynthetic autotroph.

Question 7 The euglenoids are

Question 7 options: euglenoids can be all of these things.photosynthetic organisms with chloroplasts. heterotrophic organismswithout chloroplasts. flagellated freshwater unicellularorganisms.

Question 8 African sleeping sickness and Chagas disease arecaused by

Question 8 options: amoeboids found in zooplankton. euglenoidswith chloroplasts. photosynthetic protists. parasiticflagellates.

Question 9 Amoeboids feed by

Question 9 options: photosynthesis, by which they make their ownfood in their chloroplasts. phagocytosis, which occurs aspseudopods surround and engulf prey. decomposing dead organisms.absorbing nutrients from their surroundings.

Question 10 Foraminiferans and radiolarians

Question 10 options: share a clade with the amoeboids. areamoeboids with shells called tests. have pseudopods, but are notamoeboids. do not have pseudopods, though they do have shells,called tests.

Question 11 A ciliate might have __________, which dischargestructures that are useful in defense or prey capture.

Question 11 options: anal pores trypanosomes contractilevacuoles trichocysts

Question 12 Ciliates reproduce __________ and have __________ tocontrol metabolism and reproduction.

Question 12 options: both sexually and asexually; two types ofnuclei sexually; a single nucleus asexually; two types of nuclei bybinary fission; a nucleoid

Question 13 The nonmotile apicomplexan Plasmodium vivaxcauses

Question 13 options: Chagas disease. vaginitis. African sleepingsickness. malaria.

Question 14 Which phase of Plasmodium vivaxâs life cycle takesplace in the human liver? In the mosquito carrier?

Question 14 options: the sexual phase; the asexual phase theasexual phase; the sexual phase

Question 15 __________ molds are found in forests, fields, andin soil. They exist in two forms, individual amoeboid __________and diploid multinucleated __________.

Question 15 options: Slime; sporangium; flagellated cells Water;sporangium; flagellated cells Slime; cellular slime molds;plasmodial slime molds Water; cellular water molds; plasmodialwater molds

Question 16 __________ are among the most numerous of allunicellular algae in the oceans and produce a major portion of theearths oxygen supply.

Question 16 options: Red algae Sporozoa DinoflagellatesDiatoms

Question 17 The phenomenon known as red tide is caused by

Question 17 options: population explosions in dinoflagellates.population explosions in red algae. built up remains of diatoms.bacterial invasion of the phytoplankton.

Question 18 The seaweed observed on the shoreline in the northtemperate zone, sometimes called kelp, is

Question 18 options: green algae. blue-green algae. red algae.brown algae.

Question 19 Ice cream, sherbet, and cream cheese are made fromalginate, a pectinlike material produced by __________ algae. Anemulsifying agent used in cosmetics and chocolate, as well as thewrappings for sushi rolls are made from extracts or parts of__________ algae.

Question 19 options: brown; green brown; red red; green green;brown

Question 20 Saved Green algae are believed to be closely relatedto the first plants, and are classified as plants by someauthorities, because both groups

Question 20 options: have a cell wall containing cellulose.possess chlorophylls a and b. All of these choices accuratelycomplete this statement. store reserve food in the form ofstarch.

emeraldpanda238

Question 1

The process by which RNA is synthesized using DNA as a template is â¦

Select one:

a. replication

b. transcription

c. translation

d. inspiration

Question 2

Which of the following occurs during meiosis but not mitosis?

Select one:

a. DNA condenses into chromosomes

b. nuclear envelop disappears

c. homologous chromosomes separate

d. sister chromatids separate

Question 3

Which part of the animal life cycle is haploid?

Select one:

a. gamete

b. zygote

c. sporophyte

d. spore

Question 4

Single celled eukaryotic organisms are â¦

Select one:

a. viruses

b. bacterial

c. archaea

d. protists

Question 5

Which type of cellular division results in the formation of diploid cells from a diploid parent cell?

Select one:

a. mitosis

b. meiosis

c. interphase

d. A and B but not C

e. all of the above

Question 6

A sequence of DNA that codes for a single protein is a â¦

Select one:

a. gene

b. ribosome

c. mRNA

d. none of the above

Question 7

Which of the following is characteristic of animals?

Select one:

a. heterotrophic

b. sexual reproduction

c. embryonic development

d. all of the above

Question 8

All genes have only two possible alleles.

Select one:

True

False

Question 9

The presence of membrane-bound organelles is characteristic of â¦

Select one:

a. prokaryotes

b. viruses

c. bacteria

d. eukaryotes

Question 10

What are the building blocks of proteins?

Select one:

a. fatty acids

b. amino acids

c. nucleic acids

d. all of the above

Question 11

During which phase of the cell cycle does DNA replication occur?

Select one:

a. Mitosis

b. Interphase

c. Meiosis

d. Replicosis

Question 12

Which of the following characteristic is shared among fungi and animals?

Select one:

a. autotrophic

b. heterotrophic

c. cell walls

d. absorb nutrients

Question 13

A error in DNA replication that goes unrepaired is a â¦

Select one:

a. chromosome

b. chromatid

c. mutation

d. none of the above

Question 14

Alternate forms of a gene are called ________.

Select one:

a. chromatids

b. chromosomes

c. ribosomal subunits

d. alleles

Question 15

The physical expression of a genotype is the phenotype.

Select one:

True

False

Question 16

In complete dominance, a heterozygous genotype results in â¦

Select one:

a. a recessive phenotype

b. a dominant phenotype

c. a third and unique phenotype

d. none of the above

Question 17

Which theory explains the evolution of eukaryotes from prokaryotes?

Select one:

a. phagocytosis

b. endosymbiosis

c. pinocytosis

d. none of the above

Question 18

Which scientist experimented with plants to describe patterns of inheritance?

Select one:

a. Mendel

b. Chase

c. Einstein

d. Watson

Question 19

Which cellular organelle contains aerobic cellular respiration?

Select one:

a. chloroplasts

b. mitochondria

c. nucleus

d. lysosome

Question 20

Which of the following statements is false?

Select one:

a. Haploid gametes are formed by meiosis

b. Mitosis forms genetically identical daughter cells

c. Mitosis results in the formation of four daughter cells from a single parent cell

d. Mitosis forms diploid daughter cells from a diploid parent cell

Question 21

The first forms of life on Earth were ________.

Select one:

a. plants

b. microorganisms

c. birds

d. dinosaurs

Question 22

Which of the following is used to separate chromosomes during nuclear division?

Select one:

a. cytoskeleton

b. microtubules

c. actin and myosin

d. amoeboid movement

e. all of the above

Question 23

Which generation is most dominant in more primitive plants?

Select one:

a. bryophyte

b. sporophyte

c. gametophyte

d. androphyte

Question 24

Which of the following is characteristic of plants?

Select one:

a. autotrophic

b. contain chloroplasts

c. multicellular

d. all of the above

Question 25

During which phase of mitosis do chromosome line up along the middle of the cell?

Select one:

a. prophase

b. metaphase

c. anaphase

d. telophase

Question 26

During which phase of mitosis does DNA condense into distinct chromosomes?

Select one:

a. prophase

b. metaphase

c. anaphase

d. telophase

Question 27

The process by which DNA is used as a template to make new DNA is â¦

Select one:

a. translation

b. replication

c. transcription

d. allocation

Question 28

Which of the following is characteristic of plant but not animal cells?

Select one:

a. chloroplasts

b. water vacuole

c. cell wall

d. all of the above

Question 29

Which meiotic division is most like mitosis?

Select one:

a. Meiosis I

b. Meiosis II

c. Meiosis III

d. Meiosis IV

Question 30

Which enzyme catalyzes replication?

Select one:

a. DNA polymerase

b. RNA polymerase

c. Ribosome

d. all of the above

What is a genome? What is a genome made of? Describe the bacterial genome. How do bacteria reproduce? What is binary fission? Distinguish between a chromosome and chromatin. Where are chromosomes located in eukaryotic cells? What is the chromosome made of? What is a centromere? What is the centromere's role? What are sister chromatids and how do they arise? Distinguish between somatic cells and germ (gametes) cells. Describe the cell cycle. What are the different phases? What occurs during S phase? What is interphase? How is the cell cycle controlled?

Describe mitosis. What are the phases of mitosis? What occurs in each of the phases of mitosis? What is cytokinesis? How does this differ between plant and animal cells? What is a kinetochore? Where does it form? What is its role? What is the role of microtubules in mitosis? What is a centriole and what is it composed of? What is a centrosome and what is its role in mitosis? What is the metaphase plate and why is this important? What is the mitotic spindle, its role and its makeup? What defines a diploid cell? How many copies of each chromosome is in a diploid cell? What about a haploid cell? Why do the daughter cells of mitosis always have the same complement of chromosomes?

Describe meiosis. What are the phases of meiosis? What occurs in each of the phases of meiosis? Distinguish between meiosis I and meiosis II and describe how each of these processes compare to mitosis. Why do animal cells undergo meiosis? What is a gamete? What is a zygote? What are recombination, crossing-over, and chiasma? When and why does this occur? What is meant by 'homologous pair of chromosomes'? Why don't the daughter cells of meiosis have the same genetic makeup? What controls the segregation of chromosomes into the gametes?

What are genetic characters? What are genetic traits? What is an allele? What is a locus? How many alleles at each locus would a human cell have and why? Distinguish between genotype and phenotype. What is meant by a dominant gene? What is meant by a recessive gene? How do these differ? What is the genotype of a homozygous dominant organism? What is its phenotype? What is the genotype of a homozygous recessive organism? What is its phenotype? What is the genotype of a heterozygous organism? What is its phenotype? What is a genetic cross? Distinguish between the P, F1, and F2 generations. What is a true-breeding line? What is the genotype and phenotype of a cross between homozygous dominant and homozygous recessive parents? If the F1 progeny are crossed, what would be the genotype and phenotype of the F2 generation? What would be the phenotypic ratio? What would be the genotypic ratio? Be ready to generate Punnet square tests or probability analyses of crosses involving more than one genetic locus. Describe a dihybrid cross where two alleles are homozygous dominant in one parent and homozygous recessive in the other. What would be the phenotypic ratio of the F2 generation from this dihybrid cross? What is meant by independent assortment? Be prepared to calculate probabilities resulting from different crosses.

Distinguish between complete and incomplete dominance. How would incomplete dominance alter the results of a hybrid cross? What would the resulting F2 generation phenotype and genotype ratios be? What is codominance? How does this affect the results of crosses? Be prepared to determine likely blood types of parents based on the blood types of their offspring. What is a polygenic trait? What is a carrier state for a genetic disease? What is meant by linked genes? How does this affect expected outcomes of genetic crosses? How is gene linkage used for chromosomal mapping? Distinguish between autosomes and sex chromosomes. What sex chromosomes are found in women? What sex chromosomes are found in men? What are sex-linked traits? Be prepared to give the results of crosses that involve sex-linked recessive traits. What is the process of nondisjunction? What are the likely results? Why is this important? What is a Barr body? Recognize the genetic abnormality of Downs Syndrome, Turner's Syndrome, and Klinefelter's Syndrome.

pucewallaby221

BSC 310 Lecture Notes - Lecture 15: Microbiological Culture, Biochemical Oxygen Demand, Growth Medium

Document Summary

Get access

Related Documents

BSC 310 Lecture Notes - Lecture 11: Protozoa, Mitosis, Ribosomal Rna

BSC 310 Lecture Notes - Lecture 8: Cytoskeleton, Rubisco, Intermediate Filament

BSC 310 Lecture Notes - Lecture 65: Lipid Bilayer, Nuclear Membrane, Golgi Apparatus

Related Questions