BIOL 1406 Collin College Chapter 12, 13, 16, & 17 exam

What does cell division accomplish?

continuity of life is based on the reproduction of cells

What does meiosis produce?

spem and egg cell

What is a cell's genome?

all the DNA in a cells

Know chromosome, chromatin, somatic cells, gametes.

chromosomes- DNA molecules in cells are packed and contains protein

chromatin- cannot see distinct chromosomes yet

stomatic cells- have two sets of chromosomes, nonreproductive

gametes- have half as many chromosomes as somatic cells, reproductive cells (egg & sperm)

Describe sister chromatids, centromere.

sister chromatic- joined copies of the original chrosome, which separate during cell division

centromere- where the 2 chromatids are most closely attached

What happens to sister chromatids?

they join together then they separate during cell division

Contrast mitosis with cytokinesis.

in Eukaryotic

mitosis- cell division of the genetic material in the nucleus; sperm and egg identical

cytokinesis- division of the cytoplasm

How is meiosis different from mitosis?

gametes are produced by a variation of cell division, result in sperm & egg different from parent

Define cell cycle. M phase and interphase.

mitotic phase- mitosis and cytokinesis

interphase- cell growth and copying of chromosomes in preparation for cell division 90% of cell cycle

What are the 3 subphases of interphase?

1. G1 phase (first gap)

2. S phase (synthesis)

3. G2 phase (second gap)

What are the 5 phases of mitosis?

1. prophase

2. prometaphase

3. metaphase

4. anaphase

5. telophase

Describe the mitotic spindle, centrosome, aster.

mitotic spindle- structure made of microtubules that controls chromosome movement duirng mitosis

centrosome- animal cells, assembly of spindle microttubules

aster- array of short microtubules, extendes from each centrosome

What happens to the spindle during prometaphase? What is the kinetochore?

attach to the kinetochores of chromosomes and being the move them

kinetochore- protein complexes associated with centromeres

Describe metaphase.

stage when sister chromatids are lined up in the middle

What happens in anaphase?

sister chromatids separate and move along kinetochore microtubules toward opposite ends of cell

What is the end result of telophase?

2 genetically identical daughter cells

Compare animal and plant cytokinesis.

animal- cytokinesis occurs by process called cleavage, forms cleavage furrow

plant- cell plate forms duirng cytokinesis

Describe binary fission. What type of cells divide this way.

cell divides giving rise to two cells, each having the potential to grow to the size of the original cell. prokaryotes reproduce

What regulates the eukaryotic cell cycle?

molecular control system

What is the relationship between checkpoints and the cell cycle control system?

regulated internal and external, chckepoints determine where the cell cycle stops until a go-ahead signal is received

What is the Go phase?

the cell is neither dividing nor preparing to divide

What are cyclins, cyclin-dependent kinases and MPF?

they are two types of regulatory proteins are involved in cell cycle control

MPS (maturation-promoting factor) cyclin-Cdk complex that triggers a cells passage past the G2 checkpoint into the M phase

Describe growth factors?

proteins that are often produced by surrounding cells, cell division then not regulated

What is density-dependent inhibition?

crowded cells stop dividing

Anchorage dependence?

most animal cells, they must be attached to a substratum in order to divide

How are cancer cells different? Describe transformation, malignant tumors, metastasis.

exhibit neither density-dependent inhibition or anchorage dependence

transformation- normal cell is converted to a cancerous cell

malignant tumors- invade surrounding tissues and can metastasize (expanding/pressing against other things) exporitng cancer cells to other parts of the body

Define genetics, heredity, variation, & genes, locus.

genetics- scientific study of heredity and variation

heredity- transmission of traits from one generation to the next

variation- demonstrated by the differences in appearances taht offsrping show from parents and siblings

genes- passed to next generation via reproductive cells (sperm & egg)

locus- gene location

How are genes passed from one generation to the next?

inheritance

Differentiate asexual from sexual reproduction.

asexual- a clone is a group of genetically identical individuals from the same parent

sexual- offspring that have uniqure combinations of genes inherited from the two parents

Define somatic cell, karyotype.

somatic cell- body cell, 23 pairs of chromosomes

karyotype- ordered display of the pairs of chromosomes from a cell

Define homologous pair.

2 chromosomes in teacher pair (one from mother and one from father)

What are the sex chromosomes? Of males? Females?

determine the sex (X & Y)

females: XX

males: XY

Define autosomes.

the remaining cells (22) that are not sex cells

What is meant by diploid, haploid?

diploid- 2 sets of chromosomes (2n); cell of each pair

haploid- gamete (sperm or egg) contians a single set of chromosomes (n); contains 23 (

What is the human diploid & haploid number?

haploid- 23 chromosomes

diploid- 46 chromosomes

How many autosomes & sex chromosomes does a gamete have?

autosomes- 22

sex- 1

equal- 23 (haploid)

Define fertilization, zygote?

fertilization- union of gametes (sperm and egg)

zygots- fertilized egg; produces somativ cells by mitosis and develops into an adult

Where does meioisis occur?

animals/humans- testes and in females within the ovaries

plants- anthers to form pollen grains and within the ovary to form ovules

How do meiosis and fertilization alternate in sexual life cycles?

What does meiosis do to the chromosome number?

half it

How many cell divisions are there in meiosis?

4; prophase II, metaphase II, anaphase II, telophase II

Is there an interphase?

no

Describe events of Prophase I; synapsis, crossing over, tetrad, chiasmata.

chromosomes being to condense

-synapsis- homologous chromosomes loosely pair up aligned gene by gene main thing that seperates mitosis from miosis

-crossing over- nonsister chromatids exhange DNA segments

-tetrad- group of 4 chromatids

-chiasmata- X-shaped regions where frossing over occurred

What happens in Metaphase I?

tetrads line u p

Describe Anaphase I. What separates?

pairs of homologous chromosomes separate, one chromosomes moves toard each pole, guided by the spindle apparatus, sister chromatids reamin attached at the centromere and move as one unit toward the pole

Know what happens in Telophase I and Cytokinesis. What is the result?

beginning of telephone, each half of the cell has a haploid set of chromosomes; each chromosome still consists of 2 sister chromatids. cytokinesis usually occus simultaneously, forming 2 haploid daughter cells

Does interphase occur before Meiosis I and II?

yes

What is meiosis II similar to? How is it different?

Mitosis; no interphase, daughter cells not biploids

Describe Prophase II, Metaphase II.

What separates in Anaphase II?

sister chromatids

Describe events of Telophase II and Cytokinesis. What is the result?

in telophase II, the chromosomes arrive at opposite poles. nuclei form, and the chromosomes begin decondensing.

In cytokinesis separates the cytoplams. there are 4 daughter cells, each with a haploid set of chromomes. each daughter cell is genetically distince from the tohers and from the parent cell

What 3 events are unique to meioisis?

1. synapsis and crossing over in prophase I: Homologous chromosomes come togethre

2. at the metaphase plate, there are tetrads, instead of individual replicated chromosomes

3. at anaphase I, it is homologous chromosomes seperate

How does mutation contribute to genetic variation?

changes in an organisms DNA, original source of genetic diversity

Describe independent assortment of chromosomes.

describes how different genes independently separate from one another when reproductive cells develop

What events in meiosis contribute to genetic variation?

crossing-over and independent assortment

how is it that each zygote has its own genetic identity

random fertilization

What is recombinant DNA, what produces it?

formed by laboratory methods of genetic recombination (such as molecular cloning) to bring together genetic material from multiple sources, creating sequences that would not otherwise be found in the genome.

What did Watson & Crick do?

introduced an elegant double-helical model for the structure of deoxyribonucleic acid/DNA

What are bacteriophages? What were they used for?

viruses that effects coli

used in molecular genetics research

What is Chargraff's rule?

base composition of SNA varies between species. in any species the number of A and T bases are equal and the number of G and C bases are equal

What was Rosalind Franklin's contribution?

X-ray images of DNA let Watson to see that DNA is helical

What is semiconservative model for replication?

after replication, the strand is literally half old and half new

Describe replication, origin, bubble, replication fork.

replication- where the 2 DNA strands are separated, opening up a replication "bubble"

fork- a Y-shaped region where new DNA strands are elongating

What is the role of helicases, topoisomerase?

helices- enzymes that untwist the double helix at the replication forks

topoisomearse- corrects overwinding ahead of replication forks by breaking, swiveling, and rejoining DNA strands

What does the RNA primer do? Primase? DNA polymerase?

primer- initial nucleotide strand is a short RNA

primase- enzyme, can start and RNA chain from scratch and adds RNA nucleotids one at a time using the parental DNA as a template

DNA polymerases- catalyze the elongation of new DNA template strand

Describe antiparallel elongation? How does it add nucleotides?

structure of the double helix affects replication

adds- nucleotides only to the free e' end of a growing starnd; therefore a new DNA strand can elongate only in the 5' to 3' direction

Contrast leading and lagging strands.

leading-moving toward the replication fork, can continue a strand

lagging- must work in the direction away from replication form, makes little pieces, can connect to little pieces

What is the role of DNA ligase and Okazaki fragments?

lagging strand is synthesized as a series of segments called okazaki fragments which are joing together by the DNA ligase

How is proofreading accomplished?

How is DNA damaged?

UV rays, x-ray, tobacco

What do nucleases do?

replaces the damaged part of the DNA

How do errors contribute to evolution?

error rate after proofreading repair is low but not zero

What are telomeres? What are they associated with?

eukaryotic chromosomal DNA molecules have special nucleotide sequences at their ends

been proposed that the shortening of telomeres is connected to aging fountain of youth

What is the role of telomerase?

catalyzes the lengthening of telomeres in germ cells

How are telomerases related to cancer?

as they age, they are lower cell divisions

Describe the flow of genetic information from DNA to proteins?

leads to specific traits by dictating the synthesis of proteins

DNA -> RNA; RNA -> PROTEIN

What is gene expression

process by which DNA directs protein synthesis, 2 stages: transcription and translation

What is the role of RNA

bridge between genes and the proteins for which they cods

Define transcription. Role of mRNA

synthesis of RNA using information in DNA -> produces messenger RNA (mRNA)

Define translation. Role of tRNA, ribosomes.

synthesis of a polypeptide, using information in the mRNA -> ribosomes are sites of translation

Define codons.

triplets of nucleotides

What is the template strand?

during transcription, one of the 2 DNA strand, provides a template for odering the sequence of complementary nucleotids in an RNA transcript

Which way does translation proceed?

5' to 3' direction

What does a codon specify?

codes for amino acids (at least 20, but there are a few extra)

What is the genetic code? Reading frame?

61 code for amino acids; 3 triplets are stop signals to end translation, codons must be read in the reading frame (correct groupings) in oder for the polypeptide to be produced

What is the role of RNA polymerase in transcription? Base pairing? Promoter? Direction?

How is RNA processed? Cap? Tail? Purpose?

What is the relationship of exons and introns in RNA splicing?

What is meant by ribozyme?

when RNA molecule functions as an enzyme 6

Describe 2 ends of tRNA, anticodon? What is matched?

anticodon- specific amino acid

Describe the ribosome? Ribosomal RNA?

ribosomal RNA- 2 ribosomal subunits (large and small) are made of proteins

Know the 3 binding sites on the ribosome.

1. P site- holds tRNA that carries the growing polypeptide chain

2. A site- holds the tRNA that carries next amino acid to be added to the chain

3. E site- exit site

What are the 3 stages of translation and what happens in each?

1. initiation

-brings together mRNA & tRNA with 1st amino acid

2. elongation

-amino acids ar added one by one to the preceding amino acid

3. termination

Describe 3 parts of elongation?

What initiates termination?

stop codon in the mRNA reaches the A site of the ribosome

What are polyribosomes and what do they help the cell do?

number of ribosome can translate a single mRNA simultnaeously; lets caell make many copies of a polypeptide very quickly

Questions in book

Chapter 12: 1-7

Chapter 13: 1- 4

Chapter 16: 1-4, 8

Chapter 17: 1-5