Bio 110: Exam 2

Who is credited with the discovery of DNA

watson and crick

Who actually discovered DNA

Rosalind Franklin

Genome

Full set of DNA present in a individual

Chromosomes

Linear of circular strand of DNA (makes up the genome)

Gene

Sequence of bases that contain instructions for making a specific protein; section of chromosome

How many genes and bases do humans have

25,000 genes and 3,000 bases long

Allele

alternative form of a gene that codes for the same trait

Trait

Any single feature of an organism

Examples of traits

hair color, eye color

How many copies of chromosome do you inherit from your parents

one copy each

Do all DNA code for protein

No

How much human DNA codes for protein

2%

Who has the most amount of junk DNA

E.coli

Genotype

All the genes an organism has (genetic makeup)

Phenotype

Physical expression of genotype (outward appearance)

Transcription

Synthesis of an RNA copy of a segment of DNA

Steps of DNA into protein

DNA to transcription to RNA to translation to protein

RNA polymerase

Recognizes the start of a gene on the DNA strand and attaches RNA match

Transcription happens where

nucleus

Central dogma

Framework for understanding the sequential transfer of genetic info

Translation

mRNA is translated into protein

3 materials needed for translation

amino acids, ribosomes, and tRNA

Codon

group of 3 nucleotide bases in mRNA that specify a particular amino acid to be incorporated into a protein

Translation happens where

cytoplasm

Mutation

Alteration of the sequence of bases in DNA which can have a range of effects

Types of mutations

nucleotide substitutions and nucleotide deletions or insertions

Frameshift mutation

Nucletide insertion and Nucletide deletion

chromosomal aberrations

gene deletion, gene relocation, gene duplication

Mutation diseases are caused by what

translation of a non functioning protein

What makes fireflies light up

luciferase protein

Transgenic organism

transplanting genes from one organism to another organism

What chops up DNA via binding

restriction enzymes

Two applications of biotech

healthcare and agriculture

Polymerase does what

amplify DNA and creates two copies of interest DNA

What did biotech cure

SCID using stem cells

Process of gene therapy

replaces non functioning gene with working one using vectors

Example of a vector

virus

Can vectors reproduce

no

Difficulties with gene therapy

immune response, transfer DNA going into wrong cell, & virus wake up

Ethical dilemmas of biotech/screening

health insurance and discrimination

Who was the first recorded clone

dolly the sheep

Telomere

protective cap at the end of DNA, made of nucleotide bases, and gets shorter each cell division

Up to how many times can a cell divide

50

Hutchinson Gilford progeria

shortened telomeres which ages cells

Do eukaryotes replicate through mitosis or meiosis

both

What do somatic cells go through

mitosis

What do gametes go through

meiosis

Gap 1 (interphase)

cell makes proteins and rids waste

Gap 2 (interphase)

second period of growth and division prep

S phase

DNA synthesis and division prep

What replicates DNA

DNA polymerase

What does m phase stand for

mitosis phase

Apoptosis

programmed cell death to stop damage from the cell

Homologues

two chromosomes from each parent that code for same gene but are not genetically identical

DNA + Histones =

chromatin

DNA replication

2 copies to 2 chromosomes to sister chromatids connected by centromere

Prophase

nuclear membrane breaks down, sister chromatids condense, and spindle forms

Metaphase

sister chromatids line up at center of cell

Anaphase

sister chromatids are pulled apart to each pole

Telophase

Chromosomes uncoil, nuclear membrane reassembles and cell pinches in 2

Reasons for mitosis

growth and repair

What happens at the G1 checkpoint?

The cell checks that the chemicals needed for replication are present and for any damage to the DNA before entering S-phase

G2 checkpoint

Did DNA replicate correctly?

Spindle assembly checkpoint

Are the spindle fibers properly built and attached?

What happens to the length of telomeres on a cancer cell

Stays the same length

Benign tumor

localized non harmful mass of normal cells

Malignant tumor

cancerous cells that continuously replicate and are harmful

Metastasis tumor

Cancer is spreading to other parts of the body and is harmful

What does cancer interfere with

DNA and cell regulation

Phases of Mitosis

....

asexual reproduction

Daughter cells inherit full set of identical DNA from 1 parent cell

sexual reproduction

combination of DNA from 2 separate individuals that is passed on

Diploid

containing two complete sets of chromosomes, one from each parent.

Haploid

having only one complete set of chromosomes.

Homologues (meiosis)

maternal and paternal copies of a chromosome

Crossing over creates what

genetic variation

Prophase 1

chromosomes condense, homologous chromosome crossover and unite, nuclear membrane disappears

Metaphase 1

each pair of homologous chromosome moves to the middle

Anaphase 1

homologues are pulled apart, random assortment happens

Telophase 1

chromosomes get to poles, cytoplasm divides, and pinches into 2 daughter cells

Prophase 2

chromosomes condense, spindles form and no crossing over

Does crossing over happen in prophase 2

no

Metaphase 2

sister chromatids move to the middle

Are the sister chromatids identical in metaphase 2

no

Anaphase 2

pulls sister chromatids apart and one set goes to each pole

Telophase 2

cytoplasm divides, cell pinches into 2 and there's 4 haploid cells total

How many haploid cells does meiosis produce?

4

Why does meiosis have one large egg and one polar body

unequal division of cytoplasm

Sexual reproduction disadvantages

mate competition, parent only contributes half, and higher risk of disease

Asexual reproduction disadvantages

little genetic variability and more vulnerable to change

Meiosis starts with how many chromatids

92

Autosomes

carry genes for non sex specific traits

How many chromosomes are autosomes

22 pairs

How many chromosomes are sex chromosomes

1 pair

Who determines sex of the baby

father

Karyotype

a display of an individual's complete set of chromosomes performed on fetus

What do karyotypes show?

sex and chromosomal abnormalities

extra copy of chromosome 21

Down syndrome

Nondisjunction

the unequal distribution of chromosomes during meiosis

Turner syndrome

only one X chromosome