Chapter 2

Question 1

Why do anthropologists care about genetics?

Answer 1

• Health applications: Disease risk & effectiveness of medication - Debates concerning inheritance of complex human traits (e.g., IQ, race, assisted reproductive technologies) - Application in DNA fingerprinting (e.g., forensics, paternity testing) + “DNA barcoding”

Question 2

How are traits passed from generation to generation?

Answer 2

Genetic Inheritance: the process by which genetic information is passed on from parent to child

Question 3

How are genes (genotypes) related to physical traits (phenotypes)?

Answer 3

The genotype is the set of genes in our DNA which is responsible for a particular trait. The phenotype is the physical expression, or characteristics, of that trait. For example, two organisms that have even the minutest difference in their genes are said to have different genotypes.

Question 4

Know how to use and interpret Punnett Squares to identify genotype and phenotype frequencies

Answer 4

look at slide.

Question 5

What is DNA and how does its structure allow for easy replication?

Answer 5

DNA: The molecule that carries hereditary information • A single DNA strand contains thousands of genes. (1) First by unzipping the two strands A-G-C-T molecules easily bind to their complementary bases until “new backbones” are built (2) Enzymes help “proofread” the resulting identical copies of the double helix • During mitosis the chromosomes replicate to produce two exact copies of the genetic material that will divide and reside in the nucleus of the two daughter cells

Question 6

How does DNA “code” for proteins?

Answer 6

• Some DNA code for enzymes and other proteins • Some DNA are known as regulatory genes, which regulate how much of a particular protein gets made • Other DNA code only for a molecule quite similar to DNA known as RNA • Some DNA is simply a code for making proteins. • Collagen, keratin, myosin, insulin, and enzymes

Question 7

Functions of DNA

Answer 7

-stores an organisms genetic material in the nuclei -replicates itself when dividing -provides code or template for the particular sequencing of amino acids that bond together and make a protein

Question 8

Gene

Answer 8

Sections of DNA that code for a particular trait • Each gene will contain a sequence of A, T, C, and G that code for something • Some genes are 300 letters long, others are over a thousand letters long

Question 9

Variants and crosses

Answer 9

The particular form of a trait. For example, blue eyes, brown eyes, and gray eyes are variants of the trait eye color. - crosses: in genetics, a mating between chosen parents. (read slide)

Question 10

Genotype

Answer 10

refers to the particular combination of genes or alleles that an individual carries AA, Aa, aa • Dominant: describing an allele that results in the same phenotype whether in the homozygous or the heterozygous state (AA, Aa) • Recessive: describing an allele that is expressed in the phenotype on when it is the homozygous state (aa)

Question 11

Phenotype

Answer 11

Phenotype refers to the observable characteristics of the organism Brown hair, blond hair, brown eyes, blue eyes • Anatomical, biochemical, or behavioral trait • Knowing an individual’s observable characteristics does not necessarily tell you its genetic composition

Question 12

Homozygous

Answer 12

Referring to a diploid organism whose chromosomes carry two copies of the same allele at a single genetic locus (AA or aa)

Question 13

Heterozygous

Answer 13

Referring to a diploid organism whose cells carry two different alleles for a particular genetic locus (Aa)

Question 14

Gametes

Answer 14

in animals, egg and sperm

Question 15

Mitosis v. Meiosis (look slide).

Answer 15

Mitosis is cell division, a process that creates two copies of the chromosomes present in the nucleus. - Meiosis is a special form of cell division that leads to gametes.

Question 16

Independent assortment

Answer 16

These genes are transmitted when gametes* are formed. i. This is how variation is preserved ii. Modern scientists call this independent assortment

Question 17

Alleles

Answer 17

Different varieties of a particular gene

Question 18

Recessive

Answer 18

Recessive: describing an allele that is expressed in the phenotype on when it is the homozygous state (aa)

Question 19

Dominant

Answer 19

• Dominant: describing an allele that results in the same phenotype whether in the homozygous or the heterozygous state (AA, Aa)

Question 20

Punnett square

Answer 20

• Punnett Squares help visualize the different ways in which alleles can be combined • Shows the proportions of phenotypes and genotypes in the next generation

Question 21

Event tree

Answer 21

-

Question 22

Locus

Answer 22

Genes on a chromosome are linearly arranged, like beads on a string. These areas of the chromosome where specific genes reside are called loci.

Question 23

Linked and unlinked

Answer 23

linked : referring to genes located on the same chromosome. The closer together two loci are, the more likely theyt are to be linked. unlinked: referring to genes on different chromosomes.

Question 24

Crossing over

Answer 24

Traits on the same chromosome can become unlinked through a process called crossing over.

Question 25

Deoxyribonucleic acid (DNA)

Answer 25

The molecule that carries hereditary information • A single DNA strand contains thousands of genes

Question 26

Bases: A, G, C, T

Answer 26

• A long molecule with double strands • Backbone as alternating sugar and phosphate molecules • Attached to the phosphate is one of four molecules known as nucleotide bases • Nucleotide bases • Adenine (A) • Guanine (G) • Cytosine (C) • Thymine (T)

Question 27

Protein coding genes

Answer 27

Genes that encode instructions for making proteins.

Question 28

Regulatory genes

Answer 28

• Some DNA is known as regulatory genes, which regulate how much of a particular protein gets made - Regulatory gene: sections of DNA that regulate when and how much of a particular protein gets made at any one time, often by binding to an activator or repression

Question 29

Enzymes

Answer 29

• Speed chemical reactions and determine which ones happen at which times • Help regulate some of the biochemical pathways that happen in a cell

Question 30

Proteins

Answer 30

A large molecule that consists of a long chain of amino acids. Many proteins are enzymes catalyst; others perform structural functions.

Question 31

Amino Acids

Answer 31

• Amino acids: Genes that carry the instructions for making proteins • There are 20 different amino acid molecules that each have a unique 3D structure. • Proteins can have as little as a few or thousands of amino acids • The linear sequence of amino acids is called the primary structure of a protein

Question 32

Codons

Answer 32

DNA letters (A, G, C, T) for three-letter “words”— codons • Codons code for specific amino acids • 64 different possible three-letter codons • 3 sequences indicate where a gene starts or stops • 61 are used for the 20 amino acids that make up the proteins • Several different codon sequences code for the same amino acid

Question 33

Ribonucleic acid (RNA) mRNA, tRNA,

Answer 33

RNA - a long molecule that plays several different important roles in protein synthesis. RNA differs from DNA in that it has a slightly different chemical backbone and it contains the base uracil instead of thymine. - mRNA - Messenger RNA carries the entire transcribed gene out of the nucleus and to a part of the cell known as the ribosome. - tRNA- Each tRNA molecule consists of three nucleotide bases called an anticodon, and to each tRNA molecule a specific amino acid is bound. - ncRNA -

Question 34

Uracil

Answer 34

• Like DNA, RNA has four nucleotide bases, except instead of thymine, RNA has uracil (U instead of T). Adenine links to uracil (A-U) and cytosine links to guanine (C-G).

Question 35

Anticodon

Answer 35

the sequence of the base on a transfer RNA molecule that binds complementarily to a particular codon. For example,e for the code ATC the corresponding anticodon is TAG and because A binds to T and G to C.

Question 36

Ribosomes

Answer 36

a small organelle composed of proteins and nucleic acid that temporarily holds together that messenger RNA and transfer RNAs during protein synthesis.

Question 37

Prokaryotic/eukaryotic

Answer 37

• prokaryotic cells do not have a nucleus - prokaryotic - organisms that lack a cell nucleus or separate chromosomes. bacteria are prokaryotes. - Eukaryotic - organisms whose cells have cellular organelles, cell nuclei, and chromosome. all plants and animal are eukaryotes

Question 38

Introns and exons

Answer 38

In Eukaryotic cells, the sequence of DNA that codes for a protein (an exon) is almost always interrupted by a noncoding sequence called an intron

Question 39

Repressor

Answer 39

a protein decreases transcription of a regulated gene.

Question 40

Activator

Answer 40

a protein increases transcription of a regulated gene.