Biological Molecules and Enzymes

Question 1

sphingosine

Answer 1

like phosphoglycerides except that the glycerol is amino alcohol

Question 2

Lipoprotein

Function and composition

Answer 2

fat carrier in the blood

hydrophobic core surrounded by phospholipids and apoproteins

Question 3

T/F In absence of insulin, only brain and liver can absorb glucose

Answer 3

True

Question 4

Starch

Answer 4

Glycogen for plants

Amylopectin and amylose

alpha linkage

Question 5

Differentiate between nucleoside, nucleotide, and nucleic acid

Answer 5

Nucleoside - without phosphate (just nitrogenous base and sugar)

nucleotide - with the phosphate

nucleic acid - polymer with multiple nucleotides

Question 6

AT, GC number of hydrogen bonds

Answer 6

AT: 2 hydrogen bonds

GC: 3 hydrogen bonds

Question 7

Epigenetic

Answer 7

Changes made without changes in the nucleotie. ex. methylation

Question 8

Nucleosome

Answer 8

8 histones wrapped around DNA

Question 9

chromatin composition

Answer 9

1/3 DNA, 2/3 protein, little bit of RNA

Question 10

Heterochromatin

Answer 10

tightly coiled and condensed, transcription doesn’t happen

Question 11

Euchromatin

Answer 11

only coiled during nuclear division.

Question 12

single-copy DNA

Answer 12

• only one cop of a nucleotide sequence
• regions of euchromatin that are actively transcribed
• Long base sequences
• Low rate of mutation

Question 13

Repetitive DNA

Answer 13

• Not translated - non coding regions of DNA
• remain tightly coiled in heterochromatin
• Short base sequences
• Higher rate of mutation

Question 14

Methylation

Answer 14

adding -CH3 on cytosine nucleotide. DNA wound more tightly so there is decrease in transcription

Question 15

non-coding RNA

Answer 15

regions of RNA that doesn’t code for protein. Responsible for chemical changes in the chromatin structure

Question 16

Promoter sequence function

Answer 16

Dictates where transcription takes place and how often transcription takes place

Question 17

Is there a proofreading mechanism in transcription?

T/F: errors in RNA are called mutations

Answer 17

No

Errors in RNA are not called mutations and are not passed onto progeny

Question 18

Termination in transcription

Answer 18

Termination sequence

Rho protein

Question 19

T/F activators and repressors only occur in prokarotes

Answer 19

F

Question 20

Lac Operon: explain the positive and negative control of how lac genes are transcribed

Answer 20

Positive control: Acceleration –> CAP activated by cAMP (secondary messenger); this activates the promoter sequence and allows the initiation complex to form

Negative control: lactose binding to the repressor and taking off the operator. Taking the break off.

The presence of lactose can induce the transcription of the lac operon only when glucose is not present

Question 21

5’ cap

Answer 21

attachment site during translation

protection from degradation of exonuclease

Question 22

snRNPs

Answer 22

snurps

ribozme that catalyzes chemical reaction on mRNA

snRNPS + associated proteins - spliceosome

Question 23

Alternative splicing

Answer 23

omitting exons, adding introns, utilizing various splicing sites

ending at different termination site, using a different promoter and etc - contribute to genetic diversity

Question 24

Introns function in gene expression

Answer 24

associated with amplified protein production

Question 25

Destiny of proteins injected into the ER lumen

Answer 25

will become plasma membrane proteins of golgi, lslsome, ER, nuclear envelope, or secreted from the cell

Question 26

Primse in DNA replication

Answer 26

creates RNA primer to initiate or jump start replication on the lagging strand

Question 27

How are the primers removed in replication? How are the gaps filled?

Answer 27

RNAse H enzyme removes the primer. The gaps are filled by DNA polymerase

Question 28

Stop codons

Answer 28

UAA, UGA, UAG

Question 29

Signal for the large ribosome to join and form an initiation complex in translation

Answer 29

t-RNA carring 5'-CAU-3' sits on the P site

Question 30

What happens when a stop codon reaches the A site?

Answer 30

protein known as the release factor attaches

Question 31

Kinetochore

Answer 31

structure of protein and DNA located at the centromere of the joined chromatids of each chromosome

Question 32

Transversion vs. transition

Answer 32

Both are base-pair substitutions Transversion: purine to pyrimidine or vice versa Transition: convert within purines or pyrimidines

Question 33

Missense substitution

Answer 33

when a base pair changes a codon

Question 34

Duplication in chromosomal mutation

Answer 34

When a segment of DNA breaks free and attaches onto a homologous chromosome

Question 35

Translocation

Answer 35

Segment of DNA exchanged between chromosomes

Question 36

Transposons

Answer 36

Flanked by flanking sequences, they can excise themselves out from the chromosome and reinsert themselves at another location

Question 37

A way somatic cell can alter its genetic make up without meiosis

Answer 37

Transposition

Question 38

Gene linkage

Answer 38

When genes on a chromosome are located close together. The are more likely to cross over together

Question 39

Synaptonemal complex

Answer 39

Zipped region in chromosomes where genetic materials are being exchanged during meiosis

Question 40

single cross over vs. double cross over

Answer 40

Single cross over: exchanging genetic information just once Double cross over: exchange a part of the chromosome then gets a sub section of it back (regains some of the original segment)

Question 41

Penetrance

Answer 41

Probability of gene being expressed if it is present (binary condition, present or not)

Question 42

Expressivity

Answer 42

how much the genotype is expressed as a phenotype degree of expression of a certain trait

Question 43

Barr body

Answer 43

condensed, Inactive site on the X-chromosome. All but one X-chromosome is inactivated during interphase during gameoteogenesis. XX - one barr body XXX - two barr bodies

Question 44

Hardy-Weinberg equilibrium Equation to predict allelic frequencies in a population

Answer 44

1) no selection for the fittest organism 2) random mating 3) large population 4) immigration or emigration must not change the gene pool 5) mutational equilibrium p^2 + 2pq + q^2 = 1 p + q = 1