Cells, DNA, and proteins

Question 1

In single-cell organisms, what does cell reproduction result in?

Answer 1

The next generation of cells

Question 2

Define cytokinesis.

Answer 2

When a cell divides into two new cells

Question 3

Define mitosis.

Answer 3

The creation of two cells with nuclei identical to the parent cell

Question 4

Define meiosis.

Answer 4

The creation of four unique cells with half the chromosomes of the parent cell (called gametes)

Question 5

What are the two phases of cell division?

Answer 5

• Interphase: the majority of the cells life, where it increases its size and number of proteins and organelles in preparation for the M-phase
• M-phase: either mitosis or meiosis; the division of the nucleus, then cytokinesis divides the cytoplasm between two new cells

Question 6

Define diploid.

Answer 6

A somatic cell with two complete sets of chromosomes, one from each parent (23 each in humans)

Question 7

What are homologous pairs?

Answer 7

When chromosomes that code for the same genes pair up together in the nucleus

Question 8

Define haploid.

Answer 8

A sex cell (gamete) that has one set of chromosomes, and holds the genes that are passed on from generation to generation

Question 9

What is a chromatid?

Answer 9

One strand of a chromosome, that still has a centromere in the center

Question 10

What happens during prophase?

Answer 10

Chromosomes condense and the nucleus begins to disappear

Question 11

What happens during metaphase?

Answer 11

Chromosomes line up in the middle in single file, and spindles on either end of the cell reach for the chromosomes

Question 12

What happens during anaphase?

Answer 12

The spindles pull the chromosomes to either side (each has one chromatid)

Question 13

What happens during telophase?

Answer 13

Nuclei start to form around the two groups of chromosomes and the cell starts to divide

Question 14

How many cell divisions occur during meiosis?

Answer 14

Two

Question 15

During meiosis, what unique thing occurs in prophase I?

Answer 15

Crossing over /synapsis: the exchange of genetic material between chromosomes

Question 16

Who created the first accurate model of DNA?

Answer 16

James Watson and Francis Crick

Question 17

What is the shape of a DNA strand?

Answer 17

Double helix

Question 18

What is the monomer for DNA?

Answer 18

Nucleotide (adenine, cytosine, guanine, and thymine)

Question 19

Which nucleotides are purines and purimidines?

Answer 19

Purine: adenine and guanine
Purimidine: cytosine and thymine

Question 20

In RNA, what does adenine pair with?

Answer 20

Uracil

Question 21

When does DNA replication occur in a cell cycle?

Answer 21

During S-phase (part of interphase)

Question 22

Detail the DNA replication process.

Answer 22

• part of the double helix unwinds
• replicates in long pieces on the leading strand and small pieces (Okazaki fragments) on the lagging strand

Question 23

List the DNA replication enzymes and their roles.

Answer 23

• helicase: “unzips” DNA by breaking weak hydrogen bonds
• primase: “primer” that prepares DNA strands for replication
• DNA polymerase: “builds” by adding new nucleotides to the strands, beginning at the origin of replication (replication fork), building only in the 5’-3’ direction
• ligase: “glues” new nucleotides to the existing ones

Question 24

What does DNA stand for?

Answer 24

Deoxyribonucleic acid

Question 25

What is RNA?

Answer 25

Single-stranded genetic material that does not carry genetic information

Question 26

What special abilities does RNA have, and what is its main job?

Answer 26

Its main job is to build proteins; RNA can read and carry DNA code and leave the nucleus

Question 27

What are nucleotides made of?

Answer 27

- carbon sugar - phosphate - nitrogen base

Question 28

What is the difference between carbon sugars in DNA and RNA nucleotides?

Answer 28

DNA has 5-carbon sugar called deoxyribose; RNA has 6-carbon sugar called ribose

Question 29

What does RNA stand for?

Answer 29

Ribonucleic acid

Question 30

List the three kinds of RNA and their roles.

Answer 30

- messenger RNA (mRNA): carries copies of instructions for the assembly of amino acids into proteins from the DNA to the rest of the cell - ribosomal RNA (rRNA): makes up the major part of ribosomes, where proteins are made - transfer RNA (tRNA): takes information from mRNA and transfers amino acids to ribosomes during protein synthesis

Question 31

What is the monomer for protein?

Answer 31

Amino acids

Question 32

What are proteins, and what is their role?

Answer 32

Enzymes; catalyze and regulate chemical reactions in the body

Question 33

What are the two steps of protein synthesis?

Answer 33

- transcription: RNA is built to transcribe genetic information from DNA - translation: RNA builds proteins

Question 34

How many kinds of amino acids are there?

Answer 34

20

Question 35

What determines different proteins?

Answer 35

Different combinations of amino acids

Question 36

What are some functions of proteins?

Answer 36

- fight disease - create new body tissue - a component of all cell membranes - enzymes for digestion and other chemical reactions

Question 37

Detail what occurs during RNA transcription.

Answer 37

- copying genetic information from DNA to RNA - the DNA has the code for protein, which needs to be carried outside the nucleus by RNA because the DNA cannot leave - part of DNA temporarily unzips and is used as a template to assemble complementary nucleotides into mRNA - mRNA goes through the nucleus's pores and into the ribosome

Question 38

Detail what occurs during translation in protein synthesis.

Answer 38

- mRNA and tRNA meet in the ribosome - mRNA is decoded into a protein - tRNA carries amino acids from the cytoplasm into the ribosome - each codon of mRNA (three adjacent nitrogenous bases) codes for a specific amino acid - each tRNA has an anticodon (three complementary bases) that matches the mRNA codon - amino acids join together to make proteins

Question 39

What is a polypeptide?

Answer 39

A protein

Question 40

Where do we get amino acids?

Answer 40

From food -- protein we eat is broken down into individual amino acids and rearranged by RNA into new proteins according to our DNA code