Animal cell structure

Question 1

Plasma Membrane

Answer 1

Selective barrier and maintains cell shape; Biological membrane is double layer of phospholipids and other lipids; External membrane surrounds cell

Question 2

Nucleus

Answer 2

Place where DNA and chromatin are located; DNA synthesis and also transcription/mRNA processing

Question 3

Nuclear envelope

Answer 3

Membranous layer surrounding the nucleus; double membrane, each with lipid bilayer

Question 4

Nucleolus

Answer 4

Located inside of the nucleus; rRNA synthesis

Question 5

Nuclear lamina

Answer 5

Maintain shape of nucleus; composed of proteins underneath nuclear membrane (intermediate filaments in animals)

Question 6

Nuclear pores

Answer 6

Allow substances to get in and out of nucleus (mature mRNA)

Question 7

Ribosomes

Answer 7

In ALL cells; translation/protein synthesis
3 locations: free in cytoplasm, in endoplasmic reticulum (rough), or Mitochondria/chloroplast
Not an organelle

Question 8

Mitochondria

Answer 8

Cellular respiration and produce ATP for cell’s energy; has smooth external layer and folded internal layer into cristae; inner layer has two compartments: mitochondrial matrix and intermembrane space

Question 9

Chloroplast

Answer 9

Organelle found in leaves and other green organs in plants; contain chlorophyll and various enzymes that fxn in photosynthesis; contains thylakoid and has stroma
Fxn is photosynthesis, light rxns in thylakoid
Prokaryotes can perform photosynthesis without chloroplasts

Question 10

Thylakoid

Answer 10

membranous-sacs in chloroplast that stack to form granum

Question 11

Stroma

Answer 11

fluid internal

Question 12

Peroxisomes

Answer 12

Oxidize various substrates, create h2o2 and convert to water; perform rxns of different functions through metabolism

Question 13

Cytoskeleton

Answer 13

network of fibers extending throughout cytoplasm; function is to organize cell’s structure and activities, anchoring some organelles and facilitating movement
Three types of fibers:
Microtubules
Microfilaments
Intermediate filaments

Question 14

Microtubules

Answer 14

Hollow rods that help maintain shape of cell; 25 nm diameter 15 nm lumen; alpha and beta tubulin; chromosome movement, cell motility, and organelle movement are also fxns; interact with motor proteins and need ATP to move vesicle or organelle

Question 15

centrosome

Answer 15

place where microtubules spread out from

Question 16

Centrioles

Answer 16

Nine triplets of microtubules arranged in a ring

Question 17

Flagella and Cilia

Answer 17

Fxn is movement; beating patterns are influenced by microtubules; Flagella beats like a snake (sperm) and cilia goes back and forth laterally; Cilia is not in prokaryotes; both share common structure (microtubules ensheathed by extension from plasma membrane), basal body to anchor, and motor protein of dynein which drives beating/bending movements

Question 18

Microfilaments (actin filaments)

Answer 18

Two actin strands are intertwined, 7nm
1. Maintain cell shape
2. Change cell shape
3. Muscle contraction
4. Cytoplasmic streaming in plant cells
5. Cell motility

Question 19

cytoplasmic streaming

Answer 19

circular flow of cytoplasm within the cell, driven by actin-myosin interaction (muscle contractions)

Question 20

Intermediate filaments

Answer 20

fibrous proteins coiled into cables, 8-12 nm diameter; maintains cell shape, anchorage of nucleus and other organelles, and formation of nuclear lamina

Question 21

Cell Wall

Answer 21

In plants and some fungi; protects cell, maintains shape, and prevents excessive uptake of water; Plant cell walls are made of cellulose

Question 22

Primary Cell Wall

Answer 22

thin layer for young cell, flexible

Question 23

Middle lamina

Answer 23

Thin layer between the primary layer and adjacent cells

Question 24

Secondary Cell Wall

Answer 24

Added between plasma membrane and primary cell wall (thick and strong)

Question 25

Extracellular matrix

Answer 25

protection and regulatory; in animals cells, made of glycoproteins such ad collagen, proteoglycan, and fibronectin; constantly remodels, and binds to receptor proteins in plasma membrane called integrins (regulate cell behavior through this binding)

Question 26

Tight Junctions

Answer 26

When cells are tightly packed, preventing a leakage of extracellular fluid; membranes of neighboring cells press together

Question 27

Desmosomes

Answer 27

fasten cells together into tight sheets; anchor for cytoskeleton

Question 28

Gap junctions

Answer 28

provide cytoplasmic channels between adjacent cells

Question 29

Plasmodesmata

Answer 29

channel that perforate plant cell walls; water and small solutes pass from cell to cell

Question 30

structures unique to animals over plants

Answer 30

centrosome, intermediate filaments, flagella

Question 31

structures unique to plants over animals

Answer 31

central vacuole, chloroplast, plasmodesmata, cell wall