Biology 1001 LSU Hrincevich Exam 3 notes

All of the following may be found in a DNA nucleotide EXCEPT what? A) Deoxyribose

B) Adenine

C) Thymine

D) Phospolipid

phospholipid.

A disorder caused by nondisjunction of chromosome 21, resulting in a trisomy 21 child, is what?

Down syndrome.

A DNA nucleotide is made up of what components (in the correct sequence)?

phosphate-deoxyribose-nitrogen-base.

What is a major difference between mitosis and meiosis?

Meiosis produces haploid cells, mitosis produces diploid cells.

Growth factors stimulate what?

cyclin production

The two ends of a single chromosome are called what?

telomeres.

The genetic material in bacteria consists of what?

One circular DNA molecule.

During which phase of the eukaryotic cell cycle does DNA and chromosome

replication occur?

The S phase of interphase

How many viable (functional) haploid cells are produced by one diploid cell during

meiosis in females?

One

In animal cells, spindle microtubules originate from structures called what?

Centrioles.

Each of your body cells does/is/has/contains what?

is genetically identical to all others.

Which phase of mitosis is a "preparatory" step involving the development of spindle

microtubules?

prophase

Which of the following is the longest?

an uncondensed eukaryotic chromosome

During meiosis, maternal and paternal chromosomes can exchange genetic material

at sites called what?

Chiasmata

Which of the following is represented by birds?

Diploid life cycle

In a eukaryotic cell that is undergoing cell division, what will become a new

chromosome?

A chromatid

What are the sex-determining chromosomes of a human male?

X and Y chromosomes.

Most prokaryotes reproduce via a form of asexual reproduction called binary fission.

True or False?

True

In DNA, phosphate binds to what?

deoxyribose

The uncoiled DNA in a eukaryotic cell is much longer than the cell itself. True or

False?

True

The ant Myrmecia pilosula has the smallest number of chromosomes possible in a

eukaryote: females possess only one pair of chromosomes, and males have only one chromosome! Put another

way, female M. pilosula can be described as having the haploid condition n = 1 and the diploid condition 2n = 2.

Based on this scenario as well as your knowledge of gamete formation a female M. pilosula can produce

gametes with how many different sets of chromosomes?

2

In a typical human body cell, how many sex chromosomes are there?

2

Traits controlled by sex-linked recessive genes are expressed more often in males because of what reason?

the male has only one gene for the trait

When the two gametes that fuse to form a zygote contain different alleles of a given

gene, the offspring is what?

Heterozygous

If an individual who is homozygous for type B blood marries a heterozygous type A

individual, what is the chance that their first child will have type AB blood?

50%

whose effect is masked by a dominant allele.

A recessive allele

Yellow-seeded pea plants may be homozygous or heterozygous. To find out which, we

can cross the plants with what?

Tru-breeding green-seeded plants.

Round pea shape is dominant over wrinkled pea shape. If a round pea has a wrinkled

parent, the round pea is what?

Rr

In crossing a homozygous recessive with a heterozygote, what is the chance of getting a

homozygous recessive phenotype in the F1 generation

50%

Sex-linked traits affect only sexual characteristics. True or False?

False

In a test cross, what percentage of the offspring will have the same phenotype as the

tested parent if the parent to be tested is homozygous?

100%

In a DNA molecule, base pairing occurs between which two bases?

adenine and thymine.

Regarding the structure of DNA, which joins sugar to phosphate?

covalent bonds

A strand of DNA is a polymer of nucleotides held together by hydrogen bonds. True or

False?

False

How many bases are in a DNA molecule?

millions or billions

Watson and Crick are credited with the discovery and description of what characteristic

of the DNA molecule?

Double helix.

DNA helicase is involved in "rewinding" the strands of DNA back into a helix after

replication. True or False?

False

Newly replicated DNA strands contain (on average) one mistake for every how many base pairs?

100 million to 1 billion base pairs.

How many DNA base pairs are in a typical gene?

hundreds or thousands

In the comparison of a DNA molecule to a twisted ladder, the uprights of the ladder are what?

deoxyribose linked to phosphate

cell division in order

interphase, prophase, metaphase, anaphase, telophase, cytokinesis

The resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.

interphase

Cells reproduce by what________

Is required for growth and development

cell division

Cell division normally gives rise to what

Two daughter cells

Each daughter cell receives its own copy of the what

Parent cells DNA

The units of inheritance called what, specific segments of DNA (exons)

Genes

Specific sequences of nucleotides are what

Instructions

Process by which organism's cells grow larger or increase in number is called what

Miotic cell division

Daughter cells may what, becoming specialized for specific functions

differentiate

The repeating pattern of divide, grow, differentiate and then divide again is called the what

Cell cycle

Stem cells can " what" because they retain the ability to divide, perhaps for the entire life of the organism

Self renew

Stem cells include most of the daughter cells formed by the first few cell divisions of a _____________ __________, as well as a few adult cells

fertilized egg

Differentiate and never divide again

- I.e, most heart and brain cells cannot divide

- Once they die, they are gone forever

Permanently differentiated cells

Cell division is required for what reproduction

Sexual, asexual

In eukaryotic organisms when offspring are produced by the fusion

Sexual reproduction

Sperm and eggs

Gametes

Reproductive cells undergo a specialized type of cell division called what (reduction division)

Meiosis

Gametes have exactly ______ the genetic information of their parent cells and reestablish the full genetic complement when they fuse

Half

Bacteria and single-celled eukaryotic organisms reproduce what

forms offspring from a single parent, without having a sperm fertilize an egg

Asexual reproduction

The what consists of a relatively long period of growth followed by binary fission

(or "Splitting in two")

Prokaryotic cell cycle

What replicates, producing two identical copies, that attach to plasma membrane at nearby, but separate sites

Chromosomes

The what divides into two daughter cells, which each one genetically identical to the parent cell and containing a single, circular chromosome

Parent cell

Eukaryotic cells always have what

Multicellular chromosomes

helix wrapped around __, a cluster of protein particles

Histones

One what represents the helix wrapped 2x around the histone particle

Nucleosome

Represents a collection of multiple nucleosomes, looks like " beads on a string"

Chromatin

Are segments of the DNA of a chromosome

Genes

Each gene occupies a specific place, or what (plural, loci) on the chromosome

Locus

At the end of DNA replication, a what consists of two identical DNA double helices

Called sister chromatids

Duplicated chromosome

Eukaryotic chromosomes usually occur in what with similar genetic information

pairs

Chromosomes that contain the same genes are called what

Homologous chromosomes

Chromosomes that contain different genes are called what

Non homologous chromosomes

Cells with pairs of homologous chromosomes are called

(mean double)

Diploid

Changes in DNA sequence of one homologous chromosome may not occur in the other of the pair, these changes are called what, and make one homologue different genetically than the other

Mutations

Twenty two out of 23 pairs are called

- Similar in appearance and sequence

-Appear as pairs in diploid cells of both sexes

autosomes

The twenty-third pair is called what and are different in the male and the female

- Two X chromosomes (homogametic sex)

- One X + one Y chromosome ( heterogametic sex)

Sex chromosomes

Cells in the ovaries/testes undergo what and produce gametes that only have one member of each chromosome pair. These kinds of cells are called what

Meosis, haploid

At what, fusion sperm and egg (haploid)

produces a zygote (diploid) with two copies of each type of chromosome

Fertilization

Most eukaryotic cells spend the majority of their time in what 90%

the resting phase between successive mitotic divisions of a cell, or between the first and second divisions of meiosis.

(Cells spend 10% of their time in actual division)

Interphase

Is a time for acquisition of nutrtients and growth to proper size

G1 (growth phase 1)

Is characterized by DNA synthesis, when every chromosome is replicated

S (synthesis phase)

includes completion of cell growth and preparation for division of the cell into daughter cells

G2 (growth phase 2)

Chromosomes become visible, nuclear envelop dissolves, and spindle forms

a "preparatory" step involving the development of spindle

microtubules?

Prophase

second phase of mitosis, during which the chromosomes line up across the center of the cell and drawn to the center of the spindle

Metaphase

Cell elongates and sister chromatids are seperated and pulled apart toward the opposite poles

Anaphase

End stage of miotic cell division where nuclei reappear and form around chromatids; spindles break down.

Telophase

The cytoplasm divides into four, in animal cells the cell membrane pinches inward, and in plant cells vesicles from the Golgi apparatus form a cell plate. Resulting in two, identical daughter cells

Cytokenisis

Carbohydrate filled vesicles assemble along the cell's equator, between the daughter nuclei

Cell plate

(Nuclear division) The nucleus of the cell and the chromosomes divide

Mitosis

During what (cytoplasmic division), the cytoplasm is divided roughly equally between the daughter cells

Cytokinesis

Mitosis followed by what of the daughther cells allows a what to grow into an adult.

It allows organisms to maintain, repair, and even regenerate body parts

Differentiation

occurs in animal ovaries and testes and is a prerequisite for sexual reproduction in all eukaryotic organisms

Meiotic cell division

Meosis involves a specialized nuclear division called what, and two rounds of cytokinesis

Meiosis

Daughter cells are genetically what from the parent cell and what from each other

Different

Each sister chromatid has what structures at its centromere, to which microtubles attach ( think " hook and line")

Kinetochore

Cell division in eukaryotes is driven by what and controlled at specific what

Enzymes, checkpoints

Cell cycle is driven by proteins called

CDKs

CDK's become activated during what

G2

Chromosome condensation, Nuclear membrane breakdown, Attachment of chromosomes to the spindle are all what

Effects of CDK's

3 Major checkpoints regulate progress of the cell cycle

- At the juncture of G1 to S: Ensures that the cell's DNA is what

Suitable for replication