Genetics - Structure and mitosis

What is a nucleotide

Nitrogen base + sugar (ribose or deoxyribose) and phosphate group

Bond between phosphate and sugar

covalent bond

bond between sugar and base

covalent bond

Bond between bases

hydrogen bond

What are the four bases

Adenine, Thymine, Guanine, Cytosine

Gene

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

Complementary base pair

A with T and C with G

Mitochondria

organelle that is the site of ATP (energy) production

plasma membrane

defines cell boundaries, protects organelles

nuclear membrane

membrane that separates the nucleus from the cytoplasm

Which stage of Mitosis is this

Telephase

Which stage of mitosis is the following picture?

Metaphase

Which stage of mitosis is this

Which stage of mitosis is this

What stage

is cytokinesis part of mitosis

No, cytokinesis is not part of mitosis but it is a part of the M phase.

What is in the M Phase (Mitotic Phase)

Mitosis, cytokinesis

Direction of DNA strands

Opposite directions (antiparallel); one 5' end and one 3' end.

Helicase

Enzyme that unzips the two strands of DNA by breaking hydrogen bonds.

Template strand

Each separated DNA strand serves as a template for making a new strand.

Primase

Enzyme that makes a small piece of RNA called a primer.

Primer

Marks the starting point for the construction of a new DNA strand.

DNA polymerase

Enzyme that binds to the primer and builds the new DNA strand.

Direction of DNA synthesis

Bases can only be added in the 5' to 3' direction.

Leading strand

The DNA strand that is made continuously.

Lagging strand

Strand made in small sections because it runs in the opposite direction.

Okazaki fragments

Small sections of DNA made on the lagging strand.

Exonuclease

Enzyme that removes all RNA primers from both DNA strands.

DNA ligase

Enzyme that seals up DNA fragments in both strands to form a continuous double strand.

Semi-conservative replication

Each new DNA molecule consists of one conserved (old) strand and one new strand.

DNA stands for

Deoxyribonucleic acid

Amino acid

Building blocks of protein

How many chromosomes do humans have?

46 (23 pairs)

Chromatin

granular material visible within the nucleus; consists of DNA tightly coiled around proteins

What happens to chromatin during prophase?

It condenses into visible chromosomes.

Nucleolus during prophase

The nucleolus disappears.

Centrioles during prophase

They begin to move to opposite poles of the cell.

Spindle fibers during prophase

The spindle fibres start to form from the centrioles and attach to the centromere

chromosome vs chromatid

Chromosome is 2 chromatids together with a centromere in the middle of the chromatids and chromosome. .

Alignment in metaphase

Chromosomes line up along the metaphase plate (equator) of the cell as pulled by spindle fibres

Spindle fibers in metaphase

Fibers from opposite poles attach to the centromeres

Centrioles in metaphase

complete movement to oposite poles

Metaphase equator

end to end alignment of chromosomes results in a sister chromatid on each side of the cell

Anaphase

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

What is the order of cell division phases

Prophase, Metaphase, Anaphase, Telophase

Once separated, each chromatid is called a

chromosome

telophase

Nuclear membrane reforms around each set of chromosomes (two nucleus) Inside chromosomes decoil into chromatin

Cytokinesis

division of the cytoplasm

inward movement of cell membrane pinches into the daughter cells (animal)

DNA molecule

double helix

major cell organelles

nucleus, central vacuole, mitochondrion, ribosomes