DNA

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Where is DNA located?

In the nucleus

What does DNA contain?

Instructions for the cell

How is DNA arranged?

In chromosomes that come in pairs

How many chromosomes do humans have?

We have 23 pairs, 46 in total

What are the chromosomes in the human body?

22 of the pairs are identical to their partner and are numbered 1-22, biggest to smallest. One pair is the sex determining chromosomes, they determine what sex the human will be

What chromosomes do females have?

XX

What chromosomes do males have?

XY

Do all cells in your body have different numbers of chromosomes or do all cells have the same number of chromosomes?

Every cell in your body has exactly 23 pairs of chromosomes

What is a karyotype?

The number and appearance of chromosomes

What are homologous chromosomes?

In a pair of chromosomes, one is from their father and one is from their mother

Why are they called homologous chromosomes?

Because they are similar in size and shape and placement of genes (homo means same)

What are genes?

A small section of DNA which contains the instructions for a protein

What is chromatin?

A substance in the nucleus that contains DNA and proteins

What does each strand of chromatin contain?

One DNA molecule

What happens to chromatin during cell rest and growth?

The chromatin allows the DNA to be uncoiled and accessible, to direct the cell’s needs and activities

What happens to chromatin during eukaryotic cell division?

It becomes very tightly packed into structures called chromosomes

What is one type of nucleic acid?

DNA, it is called deoxyribonucleic acid

What does one molecule of DNA consist of?

2 strands of repeating units called nucleotides

What are nucleotides twisted into?

Double helix

What are the three components of a nucleotide?

Phosphate, pentose sugar, and a nitrogenous base

Out of these three: Phosphate, pentose sugar, and the nitrogenous base, which stay the same and which changes depending on the species and purpose of the cell?

Phosphate and pentose sugar stay the same no matter what the purpose of the cell is. The nitrogenous base changes depending on what the cell is and what species the cell is in.

Out of these three: Phosphate, pentose sugar, and the nitrogenous base, which one contains the genes?

The nitrogenous base contains the genes

What do nucleotides join together to form?

They join together to form DNA

What is the sugar phosphate backbone?

It is an alternating strand of sugar and phosphate that holds the bases in place

What are the components of a DNA strand?

The “outside vertical poles” of the DNA is made up of alternating phosphate and pentose sugar and the “ladder” in between is made of of the base

What are the four bases?

Adenine, thymine, guanine, and cytosine

Which bases pair with which bases?

Adenine and thymine are complimentary base pairs. Guanine and cytosine are complimentary base pairs.

How is the genetic code created?

The arrangement of the bases is what contains the “information”

How are genes created?

Each gene is a specific sequence of bases

Are both “sides” of the DNA molecule going the same way, or opposite ways?

Both sides of the DNA are anti-parallel strands, meaning they go opposite ways. One strand of the DNA molecule is upside down or flipped when compared to the other DNA strand

What does one gene equal?

One protein = one gene

What can proteins also be called?

Polypeptides

How long is one gene?

The length can vary from hundreds to thousands of base pairs

When are genes read?

Only when a specific protein is needed by the specific type of cell & at specific times

What are specialized proteins?

Proteins that can be grouped into enzymes, hormones, structural proteins, blood proteins, etc.

What are enzymes?

Proteins that speed up chemical reactions that occur within cells

What are hormones?

Proteins that act as chemical messengers

What are transport proteins?

Proteins that help move molecules across the cell membrane