Category 2

The event that happens during prophase I of meiosis, that ensure there is variation in the gametes is called-

• crossing over

• variation

• anaphase

• chromosome segregation

Answer explanation

During crossing over the maternal and paternal chromosomes literally cross over each other and the section that gets crossed over has a reshuffling of genes. This means that the gamete (sex cell) produced will be different from the maternal or paternal chromosome.

Which one correctly orders how DNA codes for proteins

• protein-> mRNA-> DNA

• mRNA-> protein-> DNA

• DNA-> mRNA-> protein

• mRNA-> DNA-> protein

Answer explanation

REMEMBER: DNA replicates during the S phase of interphase

To make proteins DNA must be transcribed into messenger RNA which can then leave the nucleus.

The mRNA will travel to a ribosome to make amino acids that link together to make polypeptide chains (proteins)

Tags

NGSS.HS-LS1-1

All organisms have genetic material. Genetic material is either DNA or RNA. If all organisms have Adenine, Thymine, Cytosine, and Guanine then we can assume that-

• we are not related to any other organisms

• we share a common ancestor with other organisms

• there is no assumption

Answer explanation

DNA and RNA are made up of nucleotides. All living organisms have nucleotides. Therefore we can assume that there must be a universal link between living organisms because we share these nucleotides just in different proportions and arrangements.

Tags

NGSS.HS-LS4-1

The 3 parts of a nucleotide, the monomer of nucleic acids are:

• phosphate, sugar, and base

• carbon, sugar, base

• phosphate, lipid, base

• phosphate, sugar, hydrogen

Answer explanation

A nucleotide is the monomer of nucleic acids (DNA and RNA)

A nucleotide is made up of a phosphate and sugar (that make up the backbone) and a base (A, T, C, G, or U)

The base arrangement make up the genetic code.

Mutations can sometimes be beneficial and may lead to evolution of a species. Some mutations however can lead to cancer or death. Which 2 mutations will have the GREATEST impact to an organism?

• Chromosomal (trisomy and monosomy)

• none of these

• Frameshift

• Substitution

Answer explanation

Chromosomal will always have the greatest impact since changing the chromosome number will affect many genes.

Frameshift mutations will change the instructions of the genetic code and lead to different proteins being made.

Point mutations such as substitution will not always make a difference and can sometimes be silent.

Tags

NGSS.HS-LS3-2

Which of the following shows a homozygous recessive allele pair?

• DD

• dd

• Dd

• cannot be determined

Answer explanation

The prefix homo means same, so same caps.

Recessive is lowercase letters and talks about the allele you only see if there is no dominant present.