Unit 7 - Molecular Biology Review

RMS Bio

Macromolecules

A very large organic molecule composed of many smaller molecules

Monomer

A simple compound whose molecules can join together to form polymers

Nucleotide

monomer of nucleic acids made up of a 5-carbon sugar, a phosphate group, and a nitrogenous base

Nucleic acids

macromolecules containing hydrogen, oxygen, nitrogen, carbon, and phosphorus

Deoyribose

A five-carbon sugar that is a component of DNA nucleotides

Ribose

A five-carbon sugar present in RNA

ACTG

bases found in DNA nucleotides

Chargaff's Rule

[A]=[T] and [G]=[C], they pair up across from one another forming two strands also called base pairing.

Adenine pairs with

Thymine

Guanine pairs with

Cytosine

hydrogen bond

weak attraction between a hydrogen atom and another atom

right handed helix

form of most DNA in cells

left handed helix

the form DNA does not have

sugar-phosphate backbone

The alternating chain of sugar and phosphate to which the DNA and RNA nitrogenous bases are attached

antiparallel

The opposite arrangement of the sugar-phosphate backbones in a DNA double helix.

5 prime end of DNA

the sugar's carbon that is attached to a phosphate

3 prime end of DNA

the end of the deoxyribose's sugar rings

genome

the complete instructions for making an organism, consisting of all the genetic material in that organism's chromosomes

Gene

A segment of DNA on a chromosome that codes for a specific trait

Chromosomes

threadlike structures made of DNA molecules that contain the genes; condensed DNA

Rosalind Franklin

Woman who generated x-ray images of DNA, she provided Watson and Crick with key data about DNA

Watson and Crick

Developed the double helix model of DNA.

DNA replication

the process of making a copy of DNA

Helicase

An enzyme that untwists the double helix of DNA at the replication forks.

DNA polymerase

Enzyme involved in DNA replication that joins individual nucleotides to produce a DNA molecule. It builds in the 5' to 3' direction.

ligase

An enzyme that connects two fragments of DNA to make a single fragment

semi-conservative replication

in each new DNA double helix, one strand is from the original molecule, and one strand is new

template strand

The DNA strand that provides the template for ordering the sequence of nucleotides in an mRNA transcript.

leading strand

The new continuous complementary DNA strand synthesized along the template strand in the mandatory 5' to 3' direction.

lagging strand

A discontinuously synthesized DNA strand that elongates by means of Okazaki fragments, each synthesized in a 5' to 3' direction away from the replication fork.

Okazaki fragments

Small fragments of DNA produced on the lagging strand during DNA replication, joined later by DNA ligase to form a complete strand.

G1 phase

The first gap, or growth phase, of the cell cycle, consisting of the portion of interphase before DNA synthesis begins.

Interphase

Cell grows, performs its normal functions, and prepares for division; consists of G1, S, and G2 phases

S phase

The synthesis phase of the cell cycle; the portion of interphase during which DNA is replicated.

G2 phase

The second growth phase of the cell cycle, consisting of the portion of interphase after DNA synthesis occurs.

Chromatin

uncondensed DNA

G1 checkpoint

checks for cell size, nutrients, growth factors and DNA damage

S checkpoint

checkpoint that determines if DNA has been replicated properly

G2 checkpoint

checks for cell size and DNA replication

M checkpoint

Spindle assembly checkpoint. Mitosis will not continue if chromosomes are not properly aligned.

Chromatid

one of two identical "sister" parts of a duplicated chromosome

Centromere

Area where the chromatids of a chromosome are attached

Centrioles

Cell organelle that aids in cell division in animal cells only

Centrosome

A structure in animal cells containing centrioles from which the spindle fibers develop.

Cytokinesis

Division of the cytoplasm during cell division

somatic cells

body cells

Eukaryotic cell

A cell that contains a nucleus and membrane bound organelles

Prophase

Chromosomes become visible, nuclear envelop dissolves, spindle forms

Mitosis

part of eukaryotic cell division during which the cell nucleus divides

Metaphase

Chromosomes line up in the middle of the cell

Anaphase

Phase of mitosis in which the chromosomes separate and move to opposite ends of the cell

Telophase

phase of mitosis in which the distinct individual chromosomes begin to spread out into a tangle of chromatin, the nuclear envelope reappears

Cancer

any malignant growth or tumor caused by abnormal and uncontrolled cell division

benign tumor

An abnormal mass of cells that remains at its original site in the body.

malignant tumor

A cancerous tumor that is invasive enough to impair the functions of one or more organs.

metastasis

The spread of cancer cells beyond their original site

Oncogenes

Genes that stimulate cell growth, if mutated these genes can cause uncontrolled cell growth

tumor suppressor genes

make proteins that stop cell division and kill cells

DNA mismatch repair genes

Normal function to repair DNA mismatches

Mitotic index

the ratio between the number of cells in mitosis to the total number of cells.

p53 gene

a tumor-suppressor gene that codes for a specific transcription factor that promotes the synthesis of proteins that inhibit the cell cycle