Biology - Part 5

Question 1

What are chromosomes and what do they consist of?

Answer 1

Contains genes which codes for information that specifies the production of proteins

Chromosomes consist of subunits of genes, and genes consist of DNA

Question 2

What is the central dogma of biology?

Answer 2

DNA → RNA → Protein

Question 3

What is cellular differentiation?

Answer 3

Differentiation produces more specialized cells from less specialized cells, and determines what cell types each cell will become

An embryo is formed when a fertilized egg divides and becomes a zygote. The most critical stage is called gastrulation, where individual tissue layers begin to form.

Genes of each cell regulate the process of differentiation.

Differentiation can occur in adults. Cells can divide and remain undifferentiated.

Question 4

Do stem cells remain undifferentiated?

Answer 4

Yes

Question 5

What is mitosis and what does it produce?

Answer 5

Cellular replication in which two daughter cells receive the same genetic material as the parent cell.

Makes two identical cells
2n → 2n

Question 6

What is the phase that happens prior to mitosis?

Answer 6

INTERPHASE

G1: Preparation for DNA synthesis; Transcription & Translation

S: DNA Replication

G2: Protein synthesis and cell growth in preparation for cellular division

Question 7

What does diploid mean?

Answer 7

2 sets of chromosomes; homologous chromosomes; all cells but gametes

2n!

Question 8

What are the steps of mitosis?

Answer 8

See pdf

Question 9

What is meiosis? What does haploid mean?

Answer 9

Process by which a cell ½ the genetic material

2n → 1n

Haploid (1n): 1 set of chromosomes; ONLY gametes

Question 10

What is photosynthesis and what is it used for?

Answer 10

Both produces cellular energy for an organism

Carried out by organisms that possesses chloroplast (chlorophyll: trapping green pigment)

Used to produce ATP, which provides the energy to produce glucose from CO₂ and H₂O

Question 11

What is the important equation for photosynthesis?

Answer 11

6CO₂ + 6 H₂O + energy → C₆H₁₂O₆ + 6O₂

Question 12

What are autotrophs able to do?

Answer 12

Able to produce their own food such as plants, green algae, and cyanobacteria

Question 13

What is cellular respiration?

Answer 13

Reverse of photosynthesis!

Glucose is broken down via glycolysis & Krebs Cycle in the mitochondria to produce even more ATP.

C₆H₁₂O₆ + 6O₂ -> 6CO₂ + 6 H₂O + energy

Question 14

What are heterotrophs not able to do?

Answer 14

Heterotrophs are NOT able to produce their own food.
Heterotrophs rely on cellular respiration for energy

Question 15

What is the first way mutations can occur in the genome?

Answer 15

Errors during DNA replication

During replication, DNA polymerase produces a new complementary DNA strand through base-pairing.

HOWEVER, IT DOES MAKE SPONTANEOUS ERRORS

If a mutation is OVERLOOKED, then the DNA sequence from then on is ALTERED.

Question 16

Can mutations be repaired? What is mismatch repair? Excision repair?

Answer 16

Thus, DNA repair mechanisms exist to greatly reduce error rate!

DNA polymerase has proofreading functions

Mismatch repair: removes incorrect nucleotide and replace it with the correct one; after DNA replication

Excision repair: inspect DNA for these particular types of damage and repair it; typically it’s a section of DNA, not just a nucleotide

Question 17

What is the second way mutations can occur in the genome?

Answer 17

Mutagens
Substances that causes DNA damage such as UV to chemicals

Mutations that occur in somatic cells are not inheritable
ONLY, ONLY, ONLY mutations in germ cells are inheritable

Question 18

What are phenotypes and genotypes?

Answer 18

Phenotype: physical expression of genetic traits such as color, height, shape, body characteristics, etc…

Genotype: genetic make up; genes codes for particular proteins that determine the hereditary traits

Question 19

What should we know about phenotypes?

Answer 19

BOTH genotype and environmental factors affect the phenotype of an organism.

Organisms can have different genotypes, but same phenotypes

Question 20

What is a gene? What are alleles?

Answer 20

Gene: piece of DNA that controls a particular trait

Alleles: multiple forms of the same gene

Question 21

What should we know about the Punnett square?

Answer 21

• *Dominant** (T) vs. Recessive (t) traits
• *Homozygous** (TT or tt) vs. Heterozygous (Tt)

The Punnett Square: graphical representation of all the possible combination of alleles

Question 22

What is incomplete dominance?

Answer 22

Dominant and recessive traits produce an intermediate phenotype

Think the red and white flowers example!