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1
Q

what are polypeptides?

A

the basic component of all proteins

2
Q

where are DNA molecules found?

A

in eukaryotes: in the chromosomes in the nucleus, but also in the mitochondrion

3
Q

what are the two broad classes of RNA?

w/o functions

A
  1. coding/messenger RNA
  2. noncoding RNA
4
Q

what does coding RNA do?

from nucleus/mitochondria?

A

coding/messenger RNA

> creates polypeptide sequence when decoded

> made in nucleus: needs to be exported to cytoplasm to make proteins

> made in mitochondria: used to make proteins within those organelles

5
Q

what is the function of non coding RNA?

A

non coding RNA

> do not code for proteins

> often involved in assisting the expression of other genes

> this may involve catalytic RNA molecules (ribozymes)

6
Q

what is the general flow of genetic information?

A

DNA > RNA > polypeptide

7
Q

what are two processes central in all cellular organisms?

A
  1. transcription

> DNA is used by RNA polymerase as template for synthesizing one of many different types of RNA

  1. translation

> mRNA is decoded to make polypeptides

> at ribosomes (large RNA protein complexes found in cytoplasm)

8
Q

how is genetic information encoded/decoded?

A

genetic information is encoded in the linear sequence of nucleotides in DNA

> and decoded in groups of three nucleotides at a time (triplets)

> this is in turn decoded in groups of three nucleotides (codons)

9
Q

what is the structure of both DNA and RNA?

difference?

A

large polymers with long linear backbones of alternating residues of a phosphate and a five-carbon sugar

> attached to each sugar is nitrogenous base

> DNA: sugar is deoxyribose

> RNA: sugar is ribose

10
Q

what 4 types of bases are found in DNA/RNA?

A

DNA:

  1. adenine
  2. cytosine
  3. guanine
  4. thymine

RNA:

  1. adenine
  2. cytosine
  3. guanine
  4. uracil
11
Q

how to divided bases into two classes?

A

bases

  1. purines (A and G)

> have two interlocked rings

  1. pyrimides (C, T, and U)

> have a single ring

12
Q

what is a nucleoside?

A

carbon attached to the carbon 1 (one prime) of the sugar

13
Q

what is nucleotide?

A

nucleotide

> a nucleoside with a phosphate group attached at the 5 or 3 prime carbon of the sugar is the basic repeat unit of a DNA strand

14
Q

how are the sugar residues linked in the backbone?

A

linked by 3,5 phosphodiester bonds

> phosphate links the 3’ carbon atom of one sugar to the 5’ carbon atom of the next sugar

15
Q

what bonds create the DNA helix?

A

two strands of DNA are held together by hydrogen bonds to form a duplex

16
Q

according to which rule do the base pairs form?

A

according to the Watson Crick rules

> A pairs with T

> G pairs with C

17
Q

why are the two DNA strands in a duplex described as anti-parallel?

A

the 5’ -> 3’ direction of the one strand is the opposite to that of its partner

18
Q

why is DNA replication called semi-conservative?

A

each daughter DNA duplex contains one srand from the parent molecule and one newly synthesized strand

19
Q

what are the two different types of daughter strands?

A

leading strand

> 5’ -> 3’ growth direction

lagging stand

> 3’ -> 5’ growth direction

20
Q

what is the difference in growth between the leading and lagging strand?

A

leading always has a free 3’ hydroxyl group

> allows continuous growth in the same direction as replication fork moves

lagging strand in opposite direction of replication fork

> making of DNA segments (Okazaki fragments)

> fragments joint together to form complete DNA strand

>>> DNA synthesis is semi- discontinuous

21
Q

what are “housekeeping genes?

what are other types of genes?

A

housekeeping genes:

> those genes need to be expressed in essentially all cells

other genes may be tissue specific, or time-specific

> time specific (cell cycle or stage of development)

22
Q

RNA transcription:

> what is the non template strand also called?

> what is the template strand also called?

A

template strand: antisense strand

> complementary to the RNA strand that is being synthesized

non template strand: sense strand

> is identical to the RNA strand being synthsized, exept for T replacing U

23
Q

how many hydrogen bonds has G-C basepair?

how many hydrogen bonds has A-T basepair?

A

G-C has 3 hydrogen bonds

A-T has 2 hydrogen bonds

24
Q

transcription factors are called …-acting?

promoters are called …-acting?

why?

A

transcription factors: trans- acting

promoters: cis- acting

>> transcription factors are produced by remote genes and have to migrate to their sites of actiong

>> promotors are located on the same DNA molecule as the genes that they regulate