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Flashcards in Chapter 4 Deck (50)
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1
Q

DNA stands for

A

deoxyribonucleic acid

2
Q

DNA components

A

sugar: deoxyribose
phosphate group
nitrogenous base: adenine

3
Q

Purines vs Pyrimidines

A

purines: A & G (double ring)
pyrimidines: T & C (single ring)

4
Q

each sidepiece is a backbone composed of ____ groups and ______

A

phosphate;deoxyribose

5
Q

what are the nitrogenous bases united by?

A

hydrogen bonds

6
Q

genetic instructions for synthesis of proteins

A

genes

7
Q

fine filamentous DNA material complexed with proteins

A

chromatin

8
Q

histones (2)

A
  • disk shaped clusters of proteins

- what DNA molecules wind around

9
Q

histones are divided into ______

A

nucleosomes

10
Q

2 parallel filaments of identical DNA

A

sister chromatids

11
Q

what joins two chromatids together

A

centromere

12
Q

RNA vs DNA (4)

A

RNA: 1 nucleotide; DNA: 2 nucleotides
RNA: ribose DNA:deoxyribose
RNA:uracil instead of thymine
RNA: smaller

13
Q

3 types of RNA

A

mRNA
tRNA
rRNA

14
Q

what determines the nucleotide sequence in the DNA

A

the amino acid sequence

15
Q

how many chromosomes do humans have?

A

46 chromosomes: 23 pairs

16
Q

3 stop codons

A

UGA, UAG, UAA

17
Q

start codon

A

AUG

18
Q

a sequence of 3 nucleotides that stands for one amino acid

A

base triplet

19
Q

T/F all body cells contain identical genes, except sex cells & immune cells

A

TRUE

20
Q

when a gene is activated what is made?

A

mRNA

21
Q

in transcription DNA codes for____; while mRNA codes for protein during ______

A

mRNA; translation

22
Q

enzyme that binds DNA and assembles mRNA. what signals this enzyme?

A

RNA polymerase; TATATA

23
Q

exons are ____ while introns are ____

A

sense (spliced together); non sense

24
Q

who are the 3 participants in translation?

A

mRNA, tRNA, rRNA

25
Q

what binds mRNA?then what?

A

small sub-unit then the large sub-unit binds the small sub-unit

26
Q

where does tRNA pick up the anticodon for translation?

A

from free amino acids in the cytosol

27
Q

where are proteins headed for lysosomes or secretion made?

A

ribosomes or rough ER

28
Q

is protein synthesis finished once the amino acid sequence is made? what has to happen?

A

no, the protein is functional only after it is coiled and folded into a precise secondary or tertiary structure

29
Q

chaperones

A

old proteins that help new proteins in folding into the proper shapes

30
Q

what is an example that can determine if a gene is turned on or off?

A

hormones

31
Q

how do cells synthesize other components for such as glycogen, fats, steroids, etc?

A

enzymes are proteins encoded by genes to synthesize this materials (indirect genetic control)

32
Q

Steps for DNA replication (4)

A
  1. Double helix unwinds from histone
  2. Enzyme helicase opens one short segment at a time exposing its nitrogenous bases
  3. DNA polymerase move along each stand
  4. New histones are synthesized in cytoplasm
33
Q

what is applied before DNA polymerase is attached?

A

RNA primer

34
Q

when do mutations occur?reasons?

A

-due to replication errors of environmental factors (viruses, chemical, & radiation)

35
Q

interphase includes:

A

G1, S,G2 phases

36
Q

mitosis phases?

A

prophase, metaphase, anaphase, telophase

37
Q

G0 phase

A

determined at G1 checkpoint; where the cell leaves the cell cycle and cease dividing

38
Q

the location of a particular gene on a chromosome

A

locus

39
Q

cells divide when (4):

A
  • have enough cytoplasm for 2 daughter cells
  • have replicated their DNA
  • have adequate supply of nutrients
  • stimulated by growth factor
40
Q

cells do not divide when: (2)

A
  • snugly contact neighboring cells

- nutrients or growth factors withdrawn

41
Q

different forms of gene at the same locus on 2 homologous chromosomes

A

allele

42
Q

codominant

A

both alleles are equally dominant

ex. P1 (striped) P2 (pink)= offspring (striped & pink)

43
Q

incomplete dominance

A

phenotype intermediate between traits each allele would have produced
ex. P1 (black) P2 (white)= offspring (gray)

44
Q

one gene produces multiple phenotypes

A

pleiotropy

45
Q

benign tumor (4)

A
  • easier to treat
  • slow growth
  • contained in capsule
  • WILL NOT metasize
46
Q

malignant tumor (4)

A
  • CANCER
  • fast growth
  • not enclosed
  • WILL metasize
47
Q

environmental cancer causing agents

A

carcinogens

48
Q

what percentage of cancers are hereditary

A

5% to 10%

49
Q

what causes cell division to accelerate out of control?

A

oncogenes (positive feedback)

50
Q

what can oppose the effects of oncogenes?

A

tumor-suppressor genes