Unit 4: Dna and Rna, Dna replication, Protein Synthesis, meiosis,

Question 1

what is dna and rna

Answer 1

they are nucleic acids, both made of nucleotides.
- sugar
- phosphate
- nitrogenous bases

Question 2

what are the nitrogenous bases

Answer 2

adenine (a), thymine (t dna only), guaine (G), cytosine (c), Uracil (u rna only)

Question 3

what does dba do

Answer 3

stores genetic information using its sequances of A, T, C, G

• this genetic information is the instructions to make an organisms proteins ( ex. like a recipe book for proteins)

Question 4

what does dna stand for

Answer 4

deoxyribonucleic acid

Question 5

what is the dna structure and what is it made out of.
What are the nitrogeneous bases for DNA

Answer 5

it has a double helix shape ( twisted ladder)
- deoxyribose sugar
- A,T,C,G

Question 6

where is dna stored

Answer 6

the nucleous of eukaryotes

Question 7

-what does Rna do

Answer 7

helps DNA make proteins

Question 8

what are the 3 types of rna and what do they do

Answer 8

EACH ONE HAS ITS OWN JOB
- mRNA : carries DNA message as codons
- rRna: makes up ribosomes
- trna: matches anti-codon to mRna codon to bring the correct ameino acid

Question 9

• what does rna stand for
• what is the structure of DNA

Answer 9

• Ribonucleic acid
• rna is single stranded
• made of ribose sugar

Question 10

what are the nitrogenous bases for rna and where is it found

Answer 10

• A, U, C, G
• nucleus and cytoplasm

Question 11

how do the nitrogenous bases connect

Answer 11

• held together by hydrogen bonds
  In both: c-g
  dna: a-t
  rna- a-u

Question 12

explain DNA replication

Answer 12

process of making a copy of DNA
- the DNA made during replication Is the exact same copy of the original DNA
- THIS HAPPENS IN S-PHASE OF INTERPHASE

Question 13

explain semiconservative

Answer 13

each DNA molecule consists of an original strand and a new strand

Question 14

what does dna require to replicate

Answer 14

it requires many enzymes ( proteins )

Question 15

what does the following do:
- helicase
- DNA polymerase
- ligase

Answer 15

helicase - separates DNA strands
Dna polymerase- adds nucleotides + proofreads
ligase- links new pieces of dna

Question 16

what is the central dogma

Answer 16

explains how life is determained threw DNA
DNA < RNA < proteins

Question 17

what is a gene

Answer 17

a section of dna that codes for a protein is called a gene
- the gene is read, and the message is used to make a protein

Question 18

what is photosynteisis

Answer 18

process of making proteins
2 steps: transcription and translation

Question 19

what is trancscription

Answer 19

1) mRna copies dna instructions

Question 20

what is translation

Answer 20

2) ribosomes use mRNA to make proteins

Question 21

Transcription
location:
what is invloved:
what happens:

Answer 21

location: nucleous
what is invloved: dna + rna
what happens:
- DNA unwinds where gene is
- rna polymers use DNA as a template to ake an mRna copy
- now the mRna copy can leave the nucleus

Question 22

what is a codon

Answer 22

sequance of 3 nucleotides that code for an ameino acid
- AUG is the start codon

Question 23

Translation
- location
- what
- what happens

Answer 23

• ribosomes
• mrna, ribosome (mRna), Trna
• mRna finds a rubosome and binds to it, mrna codons are read by tRna.
• tRna brings in correct AA that matches codon. aneino acid links together to form protein

Question 24

describe somatic cells

Answer 24

• Body cells
• found in body tissue + organs
• Dna in body cells arent passed to offspring
• ex. nerve cell

Question 25

describe gamates

Answer 25

- sex cells - eggs (female) sperm ( male) -dna in gamates can be passed to an offspring

Question 26

describe a chromosome

Answer 26

a condensed dna molecule with part (or all) of the genetic material of an organism - humans have 23 pairs ( 46 in total)

Question 27

there are 2 types of chromosomes: autosomes + sex chromosomes. describe them

Answer 27

autosome- chromosomes that carry traits sex chromosome- chromosomes with genes related to biological sex - XX = female -XY= male

Question 28

what are homologous chromosome

Answer 28

2 chromosomes with the same genes, but may have different versions of genes ( alles) - 1 is from mother -1 is from father

Question 29

what is a Diploid

Answer 29

(2n) - these cells have 2 copies of each chromosome - somatic cells - have homologous chromosomes

Question 30

what is a haploid

Answer 30

(n) think half- these cells have only 1 copy of each chromosome - gamates - don't have homoglous chromosomes

Question 31

what is fertilization

Answer 31

uniting of a sperm and and egg cell - results in a diploid - zygote = fertilized egg

Question 32

mitosis

Answer 32

starts with one 2n cell + ends with two 2n cells - somatic cells = more somatic cells

Question 33

meiosis

Answer 33

starts with one 2n cell and ends with four 2n cells - somatic cells= sex cells (gamates) - meiosis produces 4 sex cells that are genetically different from one another and from original cell - cells go through 2 rounds of division - results in haploid cells - reduceses chromosomes by half - only happens in sex cells

Question 34

Meiosis 1

Answer 34

seperates homologous chromosomes ( moms set seperates from dads set)

Question 35

Interphase 1

Answer 35

- G1: cells grow and preform many of their required cellular functions -S-phase: DNA us copied/ replicated - G2: makes proteins, grows

Question 36

prophase 1

Answer 36

The nuclear envelope breaks down. The chromatin condenses into chromosomes. - crossing over occurs

Question 37

metaphase 1

Answer 37

- homologous chromosomes pairs are randomly lined up in middle of cell - chromosomes are lined up along each side of cell equator -independant assortment

Question 38

anaphase 1

Answer 38

chromosomes are in pairs and are pulled away by spindle fibers -sister chromotids remain toghther

Question 39

teleophase 1

Answer 39

-nuclear membrane forms again (some species) - spindle fibers dissasimble - cell undergoes cytokenisis END RESULT: two new haploid cells w duplicated chromosomes. 46 chromosomes

Question 40

what are the two mechanisms that occur during meiosis 1

Answer 40

genetic diversity and variation

Question 41

what is crossing over

Answer 41

- homologous pairs line up on opposite sides of equator, parts of chromotids and become twisted around each other - this results in a new combination of alleles

Question 42

what is independent assortment

Answer 42

- homologous pairs line up opposite sides of equator - randomized - pairs are separated, 1 of each homologous pair ends up in daughter cell -- creates large number of possible combinations of chromosomes in daughter cells produced

Question 43

prophase 2

Answer 43

- nuclear membrane breaks down -spindle fibers assemble

Question 44

metaphase2

Answer 44

spindle fibers align chromosomes at cell equatpr - each chromosome still has two sister chromotids

Question 45

anaphase 2

Answer 45

-sister chromotids are pulled apart from each other by spindle fibers