Prova 1 de Medicina 2 de 2012 - BIOCEL

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Departamento de Biologia Celular e Molecular / Instituto de Biologia 
Curso: Medicina Data: 21/12/2012 Disciplina: Biologia Celular e Molecular 
ALUNO (A): ___________________________________________________ TURMA: ____ 
Avaliação Teórica referente ao conteúdo de Biologia Celular (valor: 6 pontos / 1 ponto cada questão) 
(Professora: Cláudia Mara Lara Melo Coutinho) 
 
QUESTÃO 1 
Células epiteliais que revestem a luz do intestino são altamente polarizadas, cuja membrana plasmática 
apical, que absorve seletivamente substâncias do lúmen, possui enzimas diferentes da membrana 
plasmática lateral, que interage com as células epiteliais vizinhas. 
 
 
a) Explique por que isto acontece de forma a criar tais domínios específicos de membrana em 
contradição à propriedade de fluidez da membrana determinada pelo movimento constante de seus 
lipídeos e proteínas constituintes. 
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b) Em relação à micrografia, descreva como foi realizada a técnica utilizada para processamento do 
material e especifique tipo de microscópio usado para visualização. 
 
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c) As pequenas esferas negras que aparecem na imagem (setas) mostram a localização da enzima de 
quebra da sacarose. Como tal marcação foi possível? Explique. 
 
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d) O que são exatamente as estruturas que se projetam na face apical da célula mostrada? Descreva 
como essas estruturas são organizadas internamente. 
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QUESTÃO 2 
 
As micrografias revelam uma mesma estrutura vista por técnicas distintas de microscopia. 
 
 
a) Explique a técnica 
utilizada para 
processamento do 
material biológico em: 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
- Figura a: 
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- Figura b: 
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b) Qual é a estrutura mostrada pelas micrografias? Dê o nome da subestrutura especificamente 
apontada pela seta na Figura b. 
 
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c) Descreva como tal estrutura é formada e qual o padrão de sua organização final. 
 
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d) Em que tipo de células essa estrutura pode ser encontrada e que funções ela pode determinar 
nessas células? 
 
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QUESTÃO 3 
 
A nucleoplasmina é uma proteína presente em alta concentração no nucleoplasma de oócitos de Xenopus. 
Experimentos de injeção dessa proteína no citoplasma dessas células e rastreamento posterior de seu 
destino revelam que elas inicialmente se ligam a filamentos citoplasmáticos que se projetam do anel 
externo do complexo do poro nuclear e posteriormente não só são vistas ao longo de toda a estrutura do 
poro como serão encontradas no interior do núcleo. 
 
Descreva os mecanismos de reconhecimento e as etapas sequenciais para importação dessa molécula. 
 
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QUESTÃO 4 
Crie uma legenda para a figura abaixo, contendo informações sobre a técnica utilizada para visualização, 
o tipo e a localização das estruturas reveladas pela imagem, e as possíveis alterações que tais estruturas 
sofrem durante a mitose de uma célula. 
 
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QUESTÃO 5 
A Figura mostra alteração no fenótipo de uma célula em resposta à ausência de um membro da 
superfamília da cinesina. Em A e C, células de embrião normal e em B e D, células de embrião com perda 
de cópias do gene que codifica uma proteína cinesina. A-C e B-D são fotos da mesma célula, onde A e B 
mostram filamentos de microtúbulos e C e D mostram mitocôndrias. Pergunta-se: 
 
 
a) Como microtúbulos e mitocôndrias foram evidenciados? Qual o tipo de microscópio usado para 
visualização? 
 
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b) O que acontece com localização das mitocôndrias das células mutantes? Explique os mecanismos 
que, uma vez alterados, mudaram o fenótipo dessa célula. 
 
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QUESTÃO 6 
 
 
 
a) Escreva nos quadros em branco o nome das estruturas que compõem a junção celular mostrada na 
micrografia. 
 
 
 
 
 
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b) Dê o nome e descreva a função da junção celular mostrada na micrografia. 
 
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c) Descreva pelo menos um tipo de patologia associada a alterações desse tipo de junção. 
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