Bio exam 3 terms

Biology 1020

What three components make up a nucleotide in a DNA or RNA strand?

A pentose (5-carbon) sugar, a phosphate group, and a nitrogen-containing base. The base and the phosphate group are attached to the sugar molecule.

A strand of DNA is formed by the _____ linking of _______ in a linear manner.

Covalent, nucleotides

Two DNA strands are twisted around one another to form a ______ ______ (two words).

Double Helix.

A ____ is the complete complement of an organism’s genetic material.

Genome

Any given nucleotide contains _____ base(s). Name the five potential bases.

Adenine (A) Guanine (G) Thymine (T) Uracil (U) and Cytosine (C)

The bases are divided into two. What are the two categories and what are their differences?

Purine bases have a double-ring structure and are found in both DNA and RNA. Pyrimidine bases have a single-ring structure. C is found in both DNA and RNA, T is only found in DNA, and U is only found in RNA.

The purine bases are ____ and ____. The pyrimidine bases are _____, _____, and _____.

1. Adenine and Guanine

2. Thymine, Uracil, Cytosine.

What does the prime symbol (5’) signify?

The number of carbons in the sugar.

The fifth carbon is ____ the ring.

Outside.

A _____ (base, phosphate) is attached to the 1’ carbon atom, and a ______ is attached to the 5’ position.

Base, phosphate.

Compared to ribose, deoxyribose lacks….

… A single oxygen atom at the 2’ position.

The prefix “deoxy-” means….

…. Without oxygen.

Nucleotides are linked together by _______ bonds.

Phosphodiester (phosphorous and oxygen).

Which molecules form the backbone of a DNA/RNA strand?

Phosphate and sugar.

The bases (A, T, G, C, U) _____ from the backbone.

Project.

Mitosis and mitotic cell division are for the ____ reproduction of cells, resulting in identical _____ cells.

Asexual, Daughter

Phases of the Eukaryotic Cell Cycle:

G1 (Gap phase 1)

S Phase (synthesis)

G2 (Gap phase 2)

Mitosis

Cytokinesis

In this phase, DNA replication occurs and copies of every chromosome are created.

S Phase

What proteins keep chromosomes connected?

Cohesin proteins

Cohesin proteins interact strongly at the _____.

Centromere.

What term is used to name each connected chromosome in a replicated chromosome pair?

Sister chromatids.

What are the complimentary base pairings in DNA?

A-T, C-G.

The DNA helixes are ___________, meaning they connect at opposite sides of each other.

Antiparallel.

How much of the genome must be replicated before cells can divide and create new daughter cells?

The entire genome.

What is the term for the manner in which DNA is replicated? What does it mean?

Semiconservative. One strand of the original parent DNA is preserved in the making of a new daughter DNA copy.

What are the spots where DNA replication begins called?

Origin(s) of Replication.

How many replication forks are at each origin of replication?

2.

DNA _____ will begin unwinding helical DNA and allow the rest of the DNA replication machinery to bind.

Helicases.

_______ works ahead of the helicase and removes any topological structures created.

Topoisomerase.

What are the main four proteins involved in DNA replication?

Primase, DNA polymerase, Ligase, DNA binding protein,

What is the function of primase in DNA replication?

It adds short RNA primers to the DNA that allow DNA polymerase to bind and begin synthesizing DNA.

What is the function of DNA Polymerase in DNA replication?

It reads a strand of DNA and synthesizes a new daughter strand that is complementary to the original. It will remove the intermediate RNA primer as it goes.

What is the function of Ligase in DNA replication?

It attached newly synthesized fragments of DNA together to form a continuous new daughter strand.

What is the function of the DNA binding protein in DNA replication?

it attaches to an unwound DNA to keep it from reattaching while DNA polymerase is binding.

What direction does DNA polymerase synthesize DNA in?

5’ (five prime) to 3’ (three prime)

One DNA polymerase moves toward the replication fork continually. This is called the ______ strand.

Leading.

The other DNA polymerase will be moving away from the replication fork and will have to restart back at the replication fork every so often. This is called the ____ strand.

Lagging.

The lagging strand generates short fragments of DNA called _________ fragments that have to be ligated together.

Okazaki.

What three factors contribute to the high fidelity of DNA replication?

1. Hydrogen bonds between A and T and C and G are more stable than mismatched base pairs.

2. DNA polymerase is unlikely to catalyze the bond formation between mismatched base pairs.

3. DNA polymerase has the ability to detect and repair mismatched base pairs.

What are the phases of Mitosis?

Prophase, prometaphase, metaphase, anaphase, telophase.

_____-dependent kinases are responsible for advancing a cell through the cell cycle whenever activated by cyclins.

Cyclin

Cyclins are proteins produced whenever the cell is progressing _______.

Properly.

________ proteins can shut down the cell cycle when things are not progressing properly.

Checkpoint

____ is the process that ensures daughter cells get the same amount of genes as parent cells.

Mitosis.

____ and ____ are the female and male gametes, respectively.

Eggs and sperm

Cells that contain one set of chromosomes are called…

…Haploids.

The ____ is a group of proteins that attaches at the centromere.

Kinetochore.

Mitosis is required for ____ reproduction. Meiosis is required for _____ reproduction.

Asexual, sexual

Microtubule growth and organization in animal cells starts at the…

…Centrosomes.

The ____ is essential for chromosome sorting.

Kinetochore.

Microtubule growth and organization start at the two…

…Centrosomes.

How do diploid cells divide into haploid cells?

Meiosis.

The bonds between sister chromatids are broken during the _____ stage of mitosis.

Anaphase.

During the first division of meiosis, the sorting mechanism separates chromosome pairs that are _______ to each other.

Homologous.

the chromosomes decondense during the _____ stage of mitosis.

Telophase.

_________ structures are formed after the association of two replicated homologous chromosomes.

Bivalent

Pairs of homologous chromosomes are joined during meiosis by a process termed…

…Synapsis.

The chromosomes are aligned midway between the spindle poles during…

…Metaphase.

After synapsis in meiosis, chromosomes undergo a process called _____ ______ (two words). This increases genetic variation.

Crossing over.

The sorting that occurs during ________ separates homologues from each other.

Meiosis I.

What is the difference in the sorting events of meiosis II and mitosis?

The starting point.

Sister chromatids are separated during what stage of meiosis?

Anaphase II.

Synapsis occurs during which stage of meiosis?

Prophase I.

What is the difference between meiosis I and meiosis II?

In meiosis I, homologous chromosomes separate. In Meiosis II, sister chromatids separate.

A _____ is formed when two haploid gametes unite during sexual reproduction.

Zygote.

Synapsis is the process of forming a ______.

Bivalent.

Which cells in animals undergo meiosis?

Certain diploid cells in the testes or ovaries.

What metaphase I event provides a mechanism for vast genetic diversity?

Random alignment.

Polyploids are…

…Organisms with 3+ chromosome pairs.

An animal is ________ (-ic) if, instead of being perfectly diploid, it is 2n+1.

Trisomic (trisomy).

The main purpose if meiosis in animals is to…

…Produce haploid sperm and egg cells.

Nondisjunction occurs when…

… Chromosomes do not separate properly during cell division.

Nondisjunction occurs during ____ or _____, and results in….

Meiosis I, Meiosis II, …Haploid cells that have too many or too few chromosomes.

Chromosomes can vary in…

…Size, location of centromere, number, and banding pattern.

Vesicles from the Golgi apparatus move along the microtubules and fuse to form the ____ ____ (two words) in the cytokinesis of plant cells.

Cell plate.

A cell wall forms between the two daughter cells in the _______ of plant cells.

Cytokinesis.

The two nuclei are separated into separate _____ _____ (two words) in the cytokinesis of plant cells.

Daughter cells.

Order of genome components by size:

Nucleotide ——> Single Strand DNA (through phosphodiester bond) ———> Double Strand DNA (through base pairings and hydrogen bonding) ———> (proteins and histones) Chromatin ——→ (all) Chromosome ———> (all) Genome

Loosely packed DNA is called _______. DNA must be packed this way for the cell to use it.

Euchromatin.

Tightly packed DNA is called ____. This DNA is stored.

Heterochromatin.

The full ________ of DNA represents the beginning of mitosis.

Compaction.

Prophase —> Interphase

• Chromosomes condense (this signals that prophase has started).

• The mitotic spindle apparatus beings forming.

• The nucleus begins to dissolve.

The mitotic ______ is composed of microtubules. They are created and organized by the ____.

Spindle, Centrosomes

What are the three types of microtubules?

Astral: Anchoring at pole

Polar: Pushing to separate poles

Kinetochore: Connect to Kinetochore proteins at centromere.

Prophase —→ Prometaphase

• Nucleolus fully dissolved

• Spindle fully formed

Prometaphase —→ Metaphase

• Metaphase checkpoint occurs

• Nuclear envelope completely disassociates into vesicles

• Spindle fully forms

• Sister chromatids attach to spindle

Metaphase ——> Anaphase

• Sister chromatids align along the metaphase plate

• Chromatids separate

• Individual chromosomes move toward the poles as kinetochore microtubules shorten

• Microtubules lengthen and push the poles apart.

Anaphase —→ Telophase

• Beginning of Cytokinesis

• Chromosomes decondense and the nuclear envelope re-forms

• Cytokinesis separates the mother cell into two daughter cells, beginning with a cleavage furrow in animal cells

The goal of mitosis is….

• growth

• repair

• regenerate

• asexual reproduction

… To make more daughter cells

Which organisms use mitosis for reproduction?

Single celled eukaryotic organisms.

Checkpoint proteins can…

… Prevent cyline from activating CDK, trigger apoptosis.

Phases of the cell cycle.

G1, S, G2 (Interphase), M ( includes mitosis. Steps of mitosis are PPMAT. M also includes cytokinesis. This happens outside of mitosis.) The cycle restarts at G1.

Gregor Mendel is credited with the:

Theory of inheritance.

Define genotype.

The combination of alleles that an individual poseses.

Mendel’s unit factors are now called _____, and their variant forms are referred to as _____.

Genes, alleles.

The law of independent assortment:

Alleles of different genes separate independently during gamete formation.

The genetic material within chromosomes is…

…DNA.

The phenotype refers to…

The physical appearance of the plant.

In a heterozygone, each member of a _________ chromosome pair carries a different allele of the same gene at the same locus.

homologous.

The physical location of a gene on a chromosome is called the gene’s _______.

Locus or loci.