Multicellular Organisms 1. 29

Question 1

What is a genome?

Answer 1

And organism with identical genes but can alter the expression of the genes

Question 2

What are the basic machinery for development that can be altered by preset and past environment?

Answer 2

Genes.

Question 3

Are homologous proteins functionally interchangeable?

Answer 3

Yes

Question 4

What is the ectoderm?

Answer 4

External sheet of epithelial cells.

Question 5

What does the ectoderm give rise to?

Answer 5

Nervous system and epidermis

Question 6

What is the endoderm and what does it give rise to?

Answer 6

1. Consists of epithelial tissue rolled interiorly

2. Gives rise to gut, lung, liver

Question 7

Where is the mesoderm and what does it give rise to?

Answer 7

1. Cells migrate in between the ectoderm and endoderm.

2. Muscle and connective tissue precursor

Question 8

What is gastrulation?

Answer 8

1. Transformation of a hollow sphere into a structure with a gut

Question 9

What is common amongst all animals that undergo development?

Answer 9

Mouth, anus, endoderm, ectoderm, mesoderm. All arranged in the same pattern also

Question 10

What are the two classes of proteins that are most important for development?

Answer 10

1. Cell adhesion/ protein signaling

2. Gene regulatory proteins: control expression of genes

Question 11

What is the purpose of gene duplication?

Answer 11

Making multiple homologs of a gene for higher order organisms

Question 12

What is a non-coding regulatory DNA that is a associated with each gene?

Answer 12

Instructions to produce a multicellular animal

Question 13

What are instructions for producing a multicellular animal that are associated with each gene?

Answer 13

Non-coding regulatory DNA

Question 14

Where do gene regulatory proteins bind to DNA?

Answer 14

Bind on DNA at regulatory elements

Question 15

WHat is the purpose of regulatory elements on the DNA?

Answer 15

Allows for binding of gene regulatory proteins

Question 16

What provides “uniqueness” to organisms when they have similar coding sequences?

Answer 16

Non-coding sequences

Question 17

What are determined cells/

Answer 17

Cells whose fate is determined into specialized cell type without influence from the environment

Question 18

What are completely undetermined cells?

Answer 18

Cells that respond rapidly to the changes in the environment

Question 19

What are cells that are committed?

Answer 19

Cells with attributes of a specific cell type but are able to change with influence from the environment

Question 20

What are unique methods to provide cellular differentiation

Answer 20

1. Asymmetric division.
2. Unequal distribution of molecules between daughter cells
3. Environment changes can influence the cells development
4. The molecules can alter gene expression

Question 21

WHat is short range signaling?

Answer 21

Cell-cell contact

Question 22

WHat is long range signaling?

Answer 22

Substances that diffuse through the extracellular medium

Question 23

What is inductive Signaling?

Answer 23

Induction of different developmental program in select cells of a homogenous group leading to altered character.

Question 24

What does irreversible imply?

Answer 24

Once achieved external signals become irrelevant

Question 25

What provides cells with memory?

Answer 25

Positive feedback which amplifies an effect especially after environment starts asymmetry

Question 26

What is a morphogen?

Answer 26

Long range inductive signal that imposes a pattern on a field of cells

Question 27

What produces a gradient of the morphogens?

Answer 27

1. Localized production of inducers that diffuse away from source 2. Production of inhibitor that diffuses away from source and block the action of uniform distribution

Question 28

What controls development of organisms?

Answer 28

Gene expression